The 100: Bellamy is incredibly protective of his younger sister Octavia. Since Octavia was born, it has been up to Bellamy to protect her. He follows Octavia down to Earth on what almost everyone believes is a suicide mission, figuring that, if the atmosphere wasn't toxic, Octavia would need his protection to survive in Earth's wilderness. If the atmosphere was toxic, Bellamy didn't want her to die alone. At the start of the series, Octavia seems to be the only person he cares about, though he quickly becomes less single-minded and becomes protective of quite a few more characters in addition to Octavia, particularly Clarke and his friends. Even when Octavia becomes the brutal and hard 'Blodreina' (Red Queen), goes off the rails in Season 5, and nearly has Bellamy executed in the fighting pits, Bellamy stills finds a part of himself will always remain protective of Octavia.
Angel: Played for laughs in an episode during which Angel and Doyle deliberately act in an over-protective fashion towards a prospective boyfriend of Cordelia's in order to mess with her.
Angel actually is a big brother, and his evil alter ego Angelus killed his little sister.
Are You Afraid of the Dark? features several big brothers in various stories that would do anything for their younger siblings:
"The Tale of the 13th Floor" — Billy for Karen.
"The Tale of the Shiny Red Bicycle" — Mike for Ben.
"The Tale of the Quicksilver" — Aaron for Doug.
"The Tale of the Hatching" — Augie for Jasmine.
Jang Ha-ri from All of Us Are Dead enters the zombie-infested high school intent on finding and rescuing her younger brother Woo-jin. The only time the normally stoic girl breaks down is when her brother sacrifices himself to save her.
Face and Murdock on The A-Team show this for each other quite a bit. Murdock is older than Face, but they both have their share of 'big brother' moments when it comes to looking out for each other.
Also, B.A., towards both of them. He's allowed to verbally abuse them and threaten them with physical violence on a regular basis, but if anyone else tries it...
A little odd in his case, seeing as, when you do some figuring, B.A. may actually be younger than Murdock, and possibly younger than/the same age as Face. He's still protective of them. But he'll never admit that he likes either of them, especially not Murdock.
Zina's cousin is very protective of her. Considering the awful prank Nedjma's group did to her, this is fully justified, and she acts a lot like Zina's big sister.
Nedjma too is protective regarding her little sister Leila, who's fourteen. She thinks Leila is trying to grow up too fast.
Sheldon acts this way to his twin sister Missy in The Big Bang Theory, however, it's subverted in that he doesn't do this so much for her sake, but because he concluded that in her loins lies the potential building blocks to create another remarkable genius like him. When Missy finds out his reasoning, she Groin Attacks him.
In The Big Valley, Nick, Heath, and especially Jarrod are very protective towards Audra. There are good examples of this in first season episodes "The Midas Man" and "Last Train to the Fair".
Billy the Exterminator: If something bad happens to Ricky, such as getting stung by a bee or wasp (Ricky's deathly allergic to stings), Billy will drop whatever they're doing to get him medical attention immediately.
In Blue Bloods, Danny is this with both Erin and Jamie, but especially with Jamie, since his gut instinct in crisis situations seems to be making sure his "kid" is safe.
A regular occurrence on Bonanza, as Hoss regularly comes to Joe's rescue whenever Joe is in trouble. It starts off as an Inverted Trope in "The Fighters," when Joe asks a simple question about perceptions of his cowardice.
Bones: Booth and Brennan toward their psychologist, Sweets. His old mentor flat-out states in one episode that Sweets — raised in an abusive home, adopted by a loving older couple who then died when Sweets was in his late teens or early 20s — is subconsciously seeking to build a surrogate family with the pair.
This is shown off nicely in a single line from Booth in the eighth season finale:
Booth: Sweets does not die today
When Sweets actually does die the next season, Booth can’t stop feeling guilty and he’s ready to take revenge until Brennan stops him.
There's also Booth and his younger brother Jared. Booth was willing to give up a massive RICO case which would have given him a promotion, a raise, and a trip to Hawaii just to get Jared off on a drunk driving charge. He was also very dubious of Jared's love interest and actually did a background check on her.
On Boy Meets World, Eric shows this toward Cory intermittently, such as when he protect Cory from a bully.
The Boys (2019): Kimiko is the older sister of her brother Kenji, which means she felt duty-bound to protect him. This makes it even worse when he's murdered with her being unable to stop his attacker.
The Brady Bunch: Very much eldest son Greg with his younger siblings, in particular brothers Peter and Bobby, but sometimes (step-)sister Marcia as well. They all get annoyed at times with this, but they know Greg will always have their back.
Breaking Bad: This is a consistent character trait for Jesse. He gets kicked out of his parents' house after they find a weed joint and think it's his. It was actually Jake's (Jesse's younger brother) joint, but Jesse willingly takes the fall so that his brother won't get in trouble. Then he stomps on the joint to discourage Jake from getting into drugs. Later on, he's supposed to act tough to intimidate a pair of meth-heads who stole their money, but gets disturbed when he breaks into their disgusting house and sees a dirty, scrawny boy clearly neglected by his drugged up parents. After he leaves with the money, he covers the boy's eyes as he leads him out of the house so he doesn't see the crushed body of his father, and calls the police to ensure the kid will be taken into child services. Even later, he seduces a recovering addict to try and sell meth to her, but gets cold feet when he discovers that she's a single mother raising a young boy (named Brock). He takes a liking to Brock, and is horrified when he discovers he's been poisoned near the end of season four, helping Walt kill the man he was led to believe was responsible (although it turned out that Walt had poisoned Brock himself to exploit Jesse's Big Brother Instinct). In the last season, his hatred of Todd begins when Todd mercilessly guns down a kid during a train robbery.
In Season 1, The oldest sibling, Anthony Bridgerton, is fiercely protective of his siblings, to where he's literally willing to die for their honor. When he finds out Nigel, whom he originally arranged to marry Daphne, attempted to force himself on her, he instantly calls off the arrangement and warns Nigel that if he so much as looks at his sister — he's a dead man.
In Season 2, Kate Sharma is fiercely protective of her little sister, Edwina, and tries her best to secure her happiness, which makes it awfully inconvenient when she develops feelings for the lord Edwina likes.
Spike takes pains to keep Buffy's sister Dawn from harm in a few episodes when Buffy or the Scoobies are unavailable to do so.
Buffy, herself, is a protective big sister to Dawn. So Dawn wouldn't be sacrificed, Buffy sacrificed herself instead to save the world.
Burden of Truth: After learning Luna's her little sister, Joanna is very protective of her, especially when she's in trouble.
In Can You Hear My Heart?, Joon Ha goes so far as to abandon his biological family to take care of a boy with a hearing disability.
Charmed: Prue and Piper both fit somewhere between this and Team Mom, with Prue definitely being closer to the motherly aspect. Piper takes up Prue's role after the latter's death, though once Phoebe and Paige get a bit older, she shifts more into Big Brother Instinct, which is very noticeable whenever one or both of the two youngest Halliwells get hurt. (The situation in "Y Tu Mummy Tambien" being a good example.)
Bryce Larkin is this for the titular character of Chuck, even though Chuck has pointed out that they were born in the same year. Bryce goes so far as to barge uninvited into the office of one of his professors — who happens to be part of the CIA — to tell him to leave Chuck alone.
In Cobra Kai: In the season 5 finale, the Miyagi-Fang students "protect the egg (Anthony LaRusso)" while Anthony uploads the video incriminating Silver to Cobra Kai.
Subverted in the Cold Case episode "Shuffle, Ball Change". The victim's brother was simultaneously protective and fond of his younger brother, and a Big Brother Bully who would beat him up. He derided his brother's ambitions to be a dancer and ultimately murdered him in a fit of jealous rage over his impending success (along with grief over his own failure as a wrestler).
In Criminal Minds, Derek Morgan definitely acts like this towards Spencer Reid, especially if he's in danger/threatened with his life. "I'm gonna get this guy's head on a pike" says it all. It's pretty funny, considering that he's the youngest in his family with two older sisters.
Derek's just the most obvious. All of the characters have this towards Reid. Emily in particular joins Morgan in this, with her Older Sister-like relationship with Reid. For evidence, just look at her taking a beating in "Minimal Loss" to save Reid from getting shot, and this line from "Amplification":
Hotch, of all people, also has this. He considers his team a part of his family and will protect them at all costs. He even looks after his own little brother.
In the CSI: Miami episode "Slaughterhouse" a bloodied but unharmed toddler is found wandering the streets by herself introduces the case where her mother, two older brothers, and an infant sibling were shot and killed and the father in surgery for a gunshot wound. Turns out when the killer started shooting the family, the oldest brother got his toddler sister to a safe place outside the house. He was also able to injure the shooter and tries to get the infant sibling out too, even after he was shot and bleeding, but the shooter manages to catch up and kill both of them. But because the shooter's injuries were severe enough, they couldn't search for the toddler sister having needed to go to the hospital for a gunshot wound.
Deet refuses to hurt her little brother Bobb'N or believe he's been twisted under the control of the Arathim. This ends up later convincing the Arathim to join the Gelflings against the Skeksis.
Rian seems to slowly become this for Brea, with the two bonding over the death of their parents and he warns her to stay away from Rek'yr because his clan worships death. In one scene where Rek'yr and Brea are standing close together, Rian can be seen standing off to the side looking disapproving.
In Dark Matter (2015), this is most of the crew's reaction to Five, the youngest member of the Raza and treated like such. Two and Six's Big Sister/Brother Instinct in particular is immediate (verging on Papa Wolf in Six's case), whereas Three's is gradual and much more reluctant but undeniable.
Dead Man's Gun: Katherine is caring and protective towards her younger sister in "Sisters of Mercy."
Matthew develops this towards Tom in Season 3 of Downton Abbey.
The Elementary version of Mycroft is the same. In fact, it's this protectiveness of Sherlock that leads Mycroft to resume his espionage career with MI6. Because if he didn't and help them track down a dangerous French gang, they were going to press treason charges against Sherlock for unwittingly aiding a terrorist plot. It's also the inherent danger of this that forces Mycroft to fake his death because if any of his enemies discovers the brothers' relation, Sherlock (and by extension, Joan) would be in extreme danger.
ER: Many of the older staff toward Carter, but particularly Greene and Benton — the latter to the point of being a Papa Wolf.
After seeing Troy getting a bit too friendly with Gia, Rue and Lexi haul him aside and threaten to sic some very mean guys on him if he tries to feel up Gia.
Throughout "The Next Episode", Lexi runs interference to prevent McKay from finding out that Cassie's with another guy.
Bright starts off being a bully in the pilot, but later on in the same episode, it's revealed he cares a lot about his younger sister and her comatose boyfriend. That's also expanded throughout the first season, to the point that his friendship with Ephram stems from his desire to keep her sister happy.
Ephram was protective of much younger Delia. Though quite realistically, they occasionally bickered.
Dr Abbott also became a sort of father figure to his sister after their father died (even though they were both already adults).
In Family Matters, Eddie occasionally had this relationship with Laura. When one of her boyfriends started a rumor that they slept together, Eddie angrily grabbed him and pinned him to the wall.
Firefly is a show that brothers and sisters over the world can watch together and feel happy, warm feelings for each other.
Simon rescued his little sister River from a bad place and is very protective of her — very much so. River, in turn, doesn't take kindly to those who mess with Simon, at one point threatening to kill Jayne with her brain following Ariel, and later tearing apart a whole cargo bay full of Reavers in the Big Damn Movie for shooting him. The Tams have an Undying Loyalty to each other, providing a lot of touching scenes.
Captain Mal Reynolds extends something like this to his entire crew, but particularly Kaylee, whom he even refers to as mei-mei or "little sister" a couple of times.
Inara is also very willing to play the Big Sister role. "Mei-mei" is most commonly used by her towards other (usually younger) female characters.
Everybody in the crew is violently protective of their lovable mechanic Kaylee.
Sam Braddock of Flashpoint is frequently frustrated and exasperated with his younger sister Natalie, but the minute she appears to be in danger, he drops everything to race to her rescue. (In his case, the instinct to protect is likely underscored by the fact that when he was nine, his other younger sister was hit by a car and died right in front of him.)
Frasier and Niles may spend most of their time squabbling and competing but it's clear that Frasier cares deeply for his younger brother and can't stand to see him in genuine pain. A large part of why Frasier was so antagonistic towards Niles' first two wives is because they treated him so poorly.
Joey is very protective of his seven sisters. When Chandler drunkenly makes out with one of them Joey is furious and gets even angrier when he learns Chandler can't tell which sister it was. While he can't bring himself to hit Chandler, he does allow Cookie (the toughest sister) to do it for him. A later episode suggests that he's still holding a grudge about it five years later and plans to stay mad for another five years.
Ross and Monica bicker a lot and didn't always get along as kids (largely due to the Parental Favoritism shown to Ross) but several episodes have shown that Ross will stand up for Monica. When she and Chandler start dating, Ross makes it clear repeatedly that while Chandler is his best friend it wouldn't stop Ross from kicking his ass if he ever hurt Monica. (Although no one takes his threats of physical intimidation seriously, much to Ross' frustration.)
Robb gives a disapproving look when his younger sister Sansa is attracted to Jerkass Joffrey Baratheon in "Winter is Coming". He stands his ground against three outlaws to protect his younger brother Bran in "A Golden Crown". Later, Robb breaks his stoic demeanor when confronting Rickard Karstark for murdering two young captive squires, yelling, "They were BOYS!" when Karstark tries to justify it. Robb personally executes Lord Karstark shortly afterward.
Jon is also protective of his younger half-siblings:
Before their family is separated early in Season 1, Jon gives his youngest sister Arya a present — her first sword Needle, which she treasures and is the only possession she keeps with her throughout the series.
Jon also takes on this role for his best friend Sam and later Olly, who are both his Watch brothers.
In Season 4, his Big Brother Instinct for his siblings is the reason his younger brother Bran is convinced not to go to Jon, despite wanting to reunite, because Jojen reminds Bran that Jon will want to protect him and keep him from going further north on an important mission to seek the three-eyed raven.
In Season 6, when Jon is reunited with his younger sister Sansa (making them the first of the Stark children to be able to reunite since Season 1), Jon tries to protect both Sansa and their younger brother Rickon from Ramsay Bolton (who is holding Rickon hostage and raped/tortured Sansa). In the Battle for Winterfell, Jon makes a desperate attempt to save Rickon from Ramsay — but Ramsay murders Rickon right in front of Jon — and when Jon finally catches up to Ramsay, he nearly beats him to death.
In Season 7, when Littlefinger (who sold Sansa into her nightmare marriage with Ramsay) goes all Creepy Uncle on Sansa, Jon threatens to killLittlefinger if Littlefinger doesn't back off. Later, when Jon learns Arya and Bran are alive but also that the Night King is approaching the Wall, he says he needs to return to Winterfell to prepare to defend against the army of the dead. He spares Theon — who betrayed the Starks and razed Winterfell — because Theon saved Sansa.
In Season 8, it's partly due to this trope (along with Never Hurt an Innocent) that convinces an anguished and resistant Jon to, in the end, kill his loveDaenerys to stop more of her destruction after he tries and fails to dissuade her from more carnage when she massacres the people of King's Landing who surrendered to her. Daenerys believes her actions are justified to achieve her vision of a new world and makes it clear she won't stop there — she intends to "liberate" the world through death and destruction, including Winterfell — where Sansa, Arya, and Bran are.
Despite being the youngest of the Stark children, Rickon reveals in "The Rains of Castamere" that he sees it as his job to protect his crippled brother Bran. Rickon is distraught when Bran sends him, his direwolf Shaggydog, and Osha to the Umbers for their protection while Bran himself goes north of the Wall. Rickon has an especially close bond with Bran because Bran and Rickon have remained together throughout all their struggles up to this point. Their father, mother, elder brothers, and sisters all had to leave Winterfell — and Rickon being parted from Bran clearly hurts him.
When Sansa Stark learns Ramsay has her brother Rickon, she is even more determined to take Winterfell back from Ramsay so she and Jon can save their little brother, prevent Ramsay's other atrocious threats, and take back their home for their family. She even displays shades of this towards her older brother Jon. Sansa purposefully dresses Jon in Stark clothes to make people properly respect him in Season 6 and does what she can to see him safe.
In the backstory of the series, Ned's big brother Brandon rode right into the Red Keep to demand a duel with Prince Rhaegar after Ned and Brandon's younger sister Lyanna was abducted. Unfortunately, the Mad King had Brandon arrested and executed.
Ned Stark is ready to go through Kingsguards, one being known as the best swordsman of his time, to save his sister Lyanna. He would even drop the Honor Before Reason and have his men gang up on his opponent, though he is a bit shocked by Reed stabbing Dayne in the back (but he gets over it quickly). Eventually, out of love for his sister, he lies to the whole world that he fathered a bastard solely to protect his nephew Jon, and honour her dying wish.
Gendry steps up to protect Arya almost immediately.
Jaime Lannister is protective of his little brother Tyrion and is the only one in their family to consistently defend him from the abuses of their father, sister, and society. This even extended to setting up the Meet Cute with Tysha, which is part of why the two of them get along so well (in the book, Tyrion explicitly narrates that his Undying Loyalty to Jaime is in thanks for giving him a taste of love). Jaime's violent ambush of Ned Stark is motivated by hearing that Tyrion has been abducted by Ned's wife Catelyn. Cersei and Oberyn both mention Jaime defending Tyrion even as a child, and he is the only major figure to publicly support Tyrion's innocence during Season 4 and it's implied that he would have dueled on his behalf if he had both hands. This culminates in Jaime defying both his father Tywin and sister Cersei by arranging with Varys to free Tyrion prior to Tyrion's execution, giving one final, loving hug before they part ways.
Meera Reed is fiercely protective of her little brother Jojen and and is deeply depressed when he is killed at the end of Season 4.
Jojen Reed is the younger child but the minute Karl and Karl's fellow mutineers threaten to hurt and rape his sister, Jojen gets very, very scary.
The only person that Bronn helps without having to be paid is Podrick Payne.
Aemon felt this way about Egg (his nickname for his younger brother, Aegon V) all his life. When he plays with Little Sam, Aegon remembers little Egg and their youth together. When he passes away, his final words is for his brother.
Aemon: Egg, I dreamed that I was old.
Tyrion Lannister has this towards most younger characters who are in similarly disadvantaged situations to his own. Just watch him talk to Sansa, Podrick, or Bran. He runs the gamut from cool older brother to protector and even seems to be trying to correct Joffrey until the little pissant becomes a lost cause. He also does this a bit with Daenerys once he bonds with her over the fact both their fathers were terrible people.
The dragons clearly love each other like the brothers they are. After being unshackled by Tyrion in Season 6, the first thing Viserion and Rhaegal do is cuddle together. When Viserion is fatally wounded, Rhaegal desperately attempts a Diving Save, and both he and Drogon are audibly distressed and are later heard mourning him with the draconic equivalent of a Death Wail.
Despite everything, Yara does make it clear over the course of the seasons that she does, in fact, care for her little brother. When Balon leaves Theon to die at the hands of the Boltons, Yara opts to go rogue and run a rescue mission. Though it amounts to little in the end, it does a lot to cast her in a better light.
When Bran offers himself as a lure for the Big Bad of the series, the Night King, Theon spends the entire fight serving as Bran's bodyguard and pulls a heroic sacrifice to protect Bran. Just before the Night King is about to kill Bran, Arya Stark charges at him and manages to kill the Night King, which destroys the Night King's army.
Jane Lynch's character in Glee: pure evil, except for her ill sister.
Finn has developed this for Kurt, especially since their parents got married. The exchange between him and Burt when Kurt decides to come back to McKinley says it all:
Burt: Keep an eye on your brother. Finn: Way ahead of you.
All the guys for Kurt. They teamed up on Karofsky once (with Puck staying out only because he was on probation) and offered to form a Secret Service perimeter around him when it was revealed that Karofsky, who had previously threatened Kurt's life, would be coming back to school.
Ghostwriter: Although they have a bit of a Sibling Rivalry, Alex is protective of his little sister Gaby. When she accidentally gets exposed to toxic waste, he can't stop worrying about her health.
Good Times. For all his goofy, idiotic behavior and his constant teasing of Thelma and Michael, JJ proved over and over again that the best way to anger him was to harm either one of them.
Gossip Girl: Chuck and Serena with Eric, Dan with Jenny (especially on the pilot). Lily's sister also counts.
The Great British Bake Off: Mel and Sue are fiercely protective of the contestants, to the extent of ensuring that no footage of them overtly crying, angry, upset, etc., ever gets aired by swooping in front of the cameras and either physically blocking the contestants from view or swearing loudly and eloquently to render the footage useless.
Frank is quite protective of Joe, more so in this series as there is a larger age gap between them compared to the original books. It especially comes out when Joe briefly gets taken hostage by Em and later by JB.
On the flipside, Joe is no slouch in the Little Brother Instinct where he hits the Tall Man with a trash can to make him release Frank.
Chet and Callie also have this for Joe, as well as for Biff and Phil to a lesser extent. At the time when Joe and Biff go missing, things were tense and awkward between Frank, Chet and Callie due to the latter two breaking up and Stacy's interference. But both Chet and Callie immediately set that aside to find Joe and Biff.
To some degree, JB develops this towards Joe and a little towards Frank as well. He went out of his way to save Joe from the Tall Man despite his claims that he only cared for himself. He also tried to warn Frank and Joe to stay away from investigating certain cases to keep them from getting hurt. When Frank accuses JB at one point of trying to run Joe over with a car, JB immediately and angrily retorts he would never hurt Joe.
Heroes: Nathan Petrelli for his little (26-year-old) brother, Peter. Sometimes... When it comes down to it, it's clear that he loves his brother.
Peter towards his niece, Claire.
Jerome from House of Anubis has this for Piper. While he initially dreaded her coming to the school, as she's an Annoying Younger Sibling who picked up on his own manipulative skills, he does truly love her, shown in scenes such as when he panicked when Rufus threatened her.
iCarly: Spencer in regards to Carly and Gibby to his little brother Guppy.
Ka Suo has a huge one towards Shi — even when for a large part of the story Shi is vastly more powerful than him, even when they find out they aren't really brothers, and even when they're on opposite sides of a war.
Xing Jiu, towards Xing Gui. He's willing to work for the Fire King because Xing Gui is seriously ill and the Fire King claims he has a cure.
The InBESTigators: Although he doesn’t want to admit it, Ezra cares deeply for his little sister Poppy. "The Case of the Sad Little Sister" highlights their relationship.
Interestingly, we see that Maudie has this for Ezra when she enters Tranquil Fury mode upon discovering he's being bullied on the group's web site in "The Case of the Distracted Detective".
Barbara Havers of Inspector Lynley is a cranky, foul-mouthed junk food addict who can't seem to work well with anyone in the police force except her partner Thomas Lynley. On the other hand, she is incredibly good with children and will go to any lengths to protect them.
In JAG, Bud Roberts is this with his little brother Mikey. Also Harm is this with his Russian half-brother Sergei.
Some of the main characters in the Kamen Rider series act as brotherly figures towards the younger characters.
Kamen Rider BLACK and Kamen Rider BLACK RX has the main character Kotaro Minami always loving children like a big brother would do. This is especially seen in RX where he lives with the Sahara family and takes care of their two younger children Shigeru and Hitomi, who both refer to Kotaro as their big brother.
Throughout the second season, the only one in which they were both regular characters, Sid's Big Brother Instinct towards Abby (who is fourteen years younger than him) often blinds him to her faults and/or leads him to make excuses for her behaviour.
Also in Season Two, Sid's son Eric is very kind and considerate towards his younger brother Michael after he is diagnosed with ADHD. Their older sister Diana, not so much.
In Merlin (2008), Arthur and the rest of the knights seem to be developing this for Merlin during Season 4. All of them were horrified when Merlin nearly died saving Arthur from the Dorocha and then warmly welcomed him back when he recovered. This protectiveness is a little misplaced since he could easily take on all of them with his powers!
Though they don't know it, they also protect him when he (rarely) needs it like when the Dorocha took his powers away. Look closely when they're exploring the abandoned village in 4x01. They're in a circle formation, casually placing Merlin in the center.
Merlin is also quite protective of Gwen, but then, so is everyone. It's been said before on this site: Seriously, don't mess with Gwen. It's a bad idea.
Gwen is this to Merlin as well. When a Lamia attacks him, sweet, gentle Gwen proceeds to scream "GET AWAY FROM HIM!", run up to said Eldritch Abomination, and stab it.
Betray her knights and she'll execute you.
Morgause. Just in Season 2, Episode 12 she smashes a door off it's hinges and gives up her entire plan just as it was about to succeed to save Morgana's life, and in Season 3, she captures Merlin and is very angry at him for hurting Morgana.
Miami Vice: When they were kids, Crockett's older brother Jake used to defend him from bullies.
The Middle consists of three siblings — Axl the oldest, Sue in the middle, and Brick the youngest. While Axl shows more affection towards his little brother, Brick, he's more emotionally closed off when it comes to his little sister, Sue. He taunts her, treats her with disdain, teases her to no end, and belittles her very existence (he never tells anyone in his school that he has a sister), but when it comes down to it, Axl shows a softer, comforting side of him when it really counts. Examples would be in episodes like The Block Party (where he gives Sue his old Jersey because he felt bad for her not making ball girl), and The Paper Route (where he gives her a little pep talk after her boyfriend dumps her for another girl, and invites her to come watch his game to cheer her up).
Million Yen Women: Minami, the oldest of the women, is protective of Midori, the youngest, and helps her grow out of her Extreme Doormat personality.
The Musketeers to D'Artagnan. Especially in Episode 4 when someone made a threatening move towards D'Artagnan, Porthos immediately stepped between them and warned the other man to not go there if he enjoyed breathing. And from the Death Glare that Athos was giving in the background, he wouldn't have let that man go near D'Artagnan, either.
Nirvana in Fire: Mu Qing is very protective of Nihuang (though the trope is inverted because he's her younger brother). After Sima Lei tried to rape Nihuang, Mu Qing beat him up and broke his leg.
In NUMB3RS, Don Eppes was always Charlie's protector and on the few occasions when criminals come after Charlie, Don becomes a Papa Wolf and decides that It's Personal. Don also shows concern that Charlie will be affected by the grim aspects of law enforcement and feels a little awkward accepting help that might conflict with Charlie's career as a professor.
From about Season 2 onwards, he starts to show elements of this towards his entire team. This is even how he begins relating to Liz Warner after their relationship ends (she doesn't seem to mind). Nikki and Charlie allude to it during "The Fifth Man" while Don is recovering from a line-of-duty injury.
Nikki: I guess we both got a little cocky, huh? You with your math, and, well, with me it's a constant state. It's usually Don who has to protect me from myself. Charlie: He's been doing that for me my whole life.
Once Upon a Time: Zelena ultimately becomes this towards Regina, running over the Black Fairy with her car when the latter attempts to kill Regina.
One of Us is Lying: Bronwyn is very protective about her little sister Maeve, not only due to being older (and the more responsible, dutiful sibling) but as a result of Maeve's having cancer before. Maeve is annoyed by this, but does admit reluctantly that it's justified at times, such as Bronwyn learning of her sending Simon naked photos and then threatening legal consequences for it (she was underage).
Felix is this for his foster sister Sarah. He can make fun of Sarah as much as he wants, but if there's anything or anyone who is threatening her, he will do anything to keep her safe. He's also determined to make sure she's never alone when she needs someone. When they were in the hospital and had just found out Sarah's young daughter Kira was going to be okay, Felix wrapped his arms around her in a bear hug and kissed her head repeatedly.
Sarah is this for Felix too. She is pissed when Alison points her gun at Felix.
The Other Two has hot-mess siblings Brooke and Carey looking after their superstar little brother when they can. Unlike the many hangers-on around Chase, Brooke and Carey love their brother and are very protective of him, often intervening when Chase is put in situations that he's not old enough to be in.
We could be sure that Hassan from Over There was like this when Colonel Roye threatened him about his sister so he could tell him where the stingers are.
In Oz, Ryan O'Reily is very protective of his younger brother, Cyril. Also Cyril, to a kind of smaller degree.
In Peaky Blinders, it wouldn't be wise to mess with Finn Shelby — he has four older siblings who are very protective of him (especially Tommy) and they also happen to be The Mafia of Birmingham. There's also Ada, who is the second youngest and the only girl of the Shelby siblings.
Power Rangers: Vida, the Pink Mystic Force Ranger, is already a pretty aggressive character. But threaten (or otherwise belittle) her sister Madison, and it doesn't matter whether you're an enemy or a colleague. Vida will tear you in half.
Whatever you do, don't mess with Jayden Shiba. His big sister Lauren will hurt you.
Basically any sibling duo of Rangers is protective over the other.
Prison Break is built of this trope. Michael is so convinced of half-brother Lincoln's innocence that he covers himself in full-body tattoos and commits a crime to be assigned to Link's prison to break him out.
In Psych, Shawn is seen several times threatening anyone who messes with his best friend (whom he sees as a brother), Gus — as he said in the finale of the Yin/Yang trilogy when Gus was being threatened, "You kill him, I kill you."
In Ready or Not (1993), Busy’s older brothers can sometimes be a pain, but they do care about her and are protective of their little sister.
Charlie Matheson is this to her little brother Danny on Revolution.
Hank a.k.a Dr. Henry Lawson is always watching out for his little brother, Evan, in Royal Pains. After their mum passed away when they were very young, their father took off, leaving them to take care of each other. So Hank raised his little bro. We see an example of a protective Hank in Season 4 Episode 2 Imperfect Storm, whereby he goes into full-panic mode searching for Evan after a firework explosion. They're both also quick to develop this for Emma, their 17-year-old half-sister who arrives in Season 6.
Sam & Cat: Even though they are not "biological" brothers, Goomer is this to Dice
Schitt's Creek: Alexis often brags about her wild adventures and kidnappings, but her older brother David reveals that he was often home alone worrying about her safety.
Surprisingly, this showed up in Scrubs, with J.D.'s normally antagonistic older brother standing up for J.D. against Dr. Cox:
Dan: "I just wanted to say a few things to you, Perry. I've never been much of a good example to my brother... Johnny will never look up to me, but when I see you two together he hangs on every word you say as if it's his entire world. If you ever let him down, you'll answer to me."
Simon & Simon: Brothers Rick and A.J. both exhibit this trope. Although Rick is older, he and A.J. are both protective of each other, as shown in almost any episode.
Tony Stonem in Skins starts off the series as a manipulative, cruel borderline Villain Protagonist. The one exception is his sister Effy. Her near-death experience at the end of Season 1 causes his Heel Realization.
Spinning Out: Kat is extremely protective of her younger sister Serena, doing this like breaking into a trailer and risking missing her own slot at sectionals to make sure she's okay.
Star Trek: Voyager: In the pilot episode, Tom Paris takes this attitude towards Harry Kim, first by stopping Quark from swindling him on DS9 and then by volunteering to be on the rescue team when he's abducted by the Caretaker. That being said, Tom also admits that he looks up to Harry for his moral fiber and overall optimism.
Jonathan may be an antisocial loner but he still loves younger brother Will dearly and gave him comfort during their parents’ messy break-up. Jonathan spends half of the first season looking for his brother and beat the shit of Steve when he dared to mock Will’s potential death. In the second Jonathan is distraught over the fact they have to essentially torture Will with heat to get the Eldritch Abomination out of him, in fact Jonathan refuses outright to hurt his baby brother at all. In Season 3 Jonathan hacks at the Mind Flyer with an axe, when it attacks Hopper's cabin and targets the kid squad.
Once he takes a few levels in kindness Steve becomes the big brother baby sitter for the kid squad protecting them from the lesser Demogorgans with a baseball bat and generally plays Team Dad (or Team Mom according to fangirls). Steve is particularly a Big Brother Mentor to Dustin in seasons 2 and 3.
Similarly Nancy once she stops being shallow invokes this expressing her concern for younger brother Mike serval times and in the most heartwarming moment cheers Dustin up during prom by dancing with him after some bitchy girls reduce him to tears. In Season 3 much like Jonathan, Nancy is more active in this role, warding off the Mind Flyer with many shotgun blasts when it attacks the group and almost takes Eleven away.
Averted with Billy and Max, to say the former treats his stepsister like shit would be a Understatement. Played straight in the finale of Season 3 as thanks to Eleven's Telepathy Billy has a Heel Realization and with the last of his strength pulls off a Heroic Sacrifice to save his Max from the Mindflayer, his last words are telling his stepsister how sorry he is.
Supernatural: Dean and Sam Winchester. This is a show that's actually about being brothers. (The bromance being fashionable this decade.)
Dean Winchester is absolutely insane on this point. 'Take care of Sammy' has been his entire life's motto. He dies for him; he sells his soul to Hell for him; he keeps going back for him no matter how screwed up things get between them or what Sam is dragged into; he takes him back no matter what... And honestly, the way the show is written, the latter two there seem to cost him more than the first. Especially seasons four and six, during which Sam is slipping into the dark side and walking around without his soul, respectively.
In Season 7, Dean acquires more "younger sibling" figures in the forms of Charlie and Kevin, relationships that extend into Season 8 and, by the looks of the trailers, Season 9. His devotion to them still isn't anything compared to that towards Sam, but these relationships are ironically healthier. And, of course, it's really sweet watching him "train" them, whether that be by taking them to get tattoos or helping them buy FBI costumes.
Sam turns it back on Dean pretty hard, himself. Even in Season One he completely flew off the handle when Dean looked to die, and season three was all about saving Dean to him, and he lost it once Dean went to Hell.
And he overpowered Satan for Dean in the Season 5 finale. Sure it saved the world, but it wasn't the world he thought about. But he's actually four years younger, and Dean practically raised him.
The angel Castiel gets adopted as an unofficial third Winchester brother some time in Season 5.note This is codified in dialogue late in Season 6 when he's going dark side on them with the best intentions like Sam did two seasons previous. Because he is young to the world and they are young to being and lack power, the 'big brother' role swaps back and forth a lot, and sometimes Dean and Cas are both big-brothering one another in the same scene. Though Dean never turns the Sam-level obsessiveness on Cas.
The evil thing doing an overwrite of Dean's mind and body in 7.06 complained that he "doesn't have relationships, no, he has applications for sainthood," which is just that raging protectiveness and self-sacrifice is the only setting he has for people he cares about. Which isn't to say he can't be a raging dick to these same people, because he can, but Big Brother's Privilege.
Actually that was referring to Dean tending to put the people he cares about on a pedestal and thus taking it pretty hard when they (inevitably) fail to live up to those expectations (most notably in Season 2 with John, Sam in Season 4, and Castiel in Season 6).
Subverted horrifically in one episode from The Twilight Zone (2002). A lonely little girl bonds with her babysitters, who she sees as friends or sister-figures. The latest one realizes that her doll collection appears to be coming alive to attack the girl, and spends the episode fighting them to save her. It then turns out that the dolls were all the previous babysitters, who the girl transformed because she was upset that they "abandoned" her when her parents came home. The current babysitter promptly freaks out and tries to explain the concept of "hired caretaker" to the girl, and is turned into a doll herself for her troubles.
In the Ultra Series, you have Zoffy, The Captain of the Ultra Brothers. He's willing to help his brothers particularly the younger ones, Ace and Taro, whenever he can.
Ultraman Leo has this between Gen and a boy named Tooru, as well as Tooru and his younger sister Kaoru. And of course, there's Leo with his actual brother Astra, to the degree that a major villain exploits their bond to pit them against the Ultra Brothers as part of a larger plan to destroy both the Earth and M78.
The Umbrella Academy (2019): Pretty much all the siblings have this towards each other, though it’s never made clear who is older. Examples include Luther towards all of his siblings, due to seeing himself as a leader, Diego towards Allison and Klaus, Allison towards Klaus and Vanya, Klaus towards Five and Allison, Five towards all of his siblings due to chronologically being older than them, Ben towards Klaus, and Vanya towards Five.
Noah is Henry's surrogate older brother and he'll do whatever he can to get him to freedom. When Henry dies in a Heroic Sacrifice to save the other runaways, Noah doesn't take it well at all.
Sam and Rosalee will do anything to shield their baby brother James from the harsh realities of slavery. Both of them have taken whippingsin his place on two separate occasions. Sam even offers up his life savings (and getting any money at all when you're a slave is quite a feat) to buy James' freedom. That particular subplot ends horribly with Sam's hanging.
The Vampire Diaries: When the tomb vampires kidnap and torture Stefan, his brother Damon massacres every vampire in the house.
Elena is insanely protective of her younger brother Jeremy, particularly after their parents die, then Jenna dies, and by the end of season 3 so does Alaric. To Elena, Jeremy's all that she has left, her only family, which is why he's so protective towards him, despite him being seventeen by season 4. It's no wonder that when Jeremy is killed by Katherine, shecompletelysnaps.
The awesome moment when Elena utters these six words. "Stay the hell away from my brother."
Moving over to the spin-off, we learn just how insane Klaus is about protecting Rebekah... he has killed every single man she ever loved out of pure spite, thinking they're not good enough for his sister (although some fans have other explanations for that behaviour). Elijah's protective too, just quite less psychotic while doing so.
This extends to their older sister Freya. Klaus enjoyed scaring off her dates. Also Marcel to Klaus's daughter Hope.
Warehouse 13: Both Pete and Myka, towards Claudia. Just try watching "Breakdown," and not awwwing a little. For her part, in Claudia's introductory episode, she breaks right into the freaking Warehouse and kidnaps one of the main characters in order to force him to help her rescue her brother Joshua, who was zapped into an interdimensional space (and not, as initially thought, killed) twelve years prior.
When Steve Jinks joins the team, he also becomes a big brother figure to Claudia, as well as becoming her best friend. They both go to extraordinary efforts to protect one another.
Wednesday: Although it's in a The Only One Allowed to Defeat You sort of way, Wednesday is protective over Pugsley. The first thing she does after finding him tied up in his locker is demand names and later sics piranhas on the bullies.
The West Wing: Toby Ziegler may try to downplay it, but it's clear that as the oldest of the senior staff he feels very protective of Sam, Josh and Charlie.
President Bartlet: Toby, are you in here sticking up for Sam? Toby: I know it's strange, sir. But I'm feeling a-a... certain big brotherly connection right now. You know, obviously, I'd like that feeling to go away as soon as possible.
On White Collar, Peter and Mozzie both have a very strong big brother instinct when it comes to Neal. The problem is, they almost always have different ideas about what actually constitutes looking out for him, which adds an extra layer of heartwarming to their park-bench meetings in "Withdrawal". They're both so worried about Neal that they actually make an effort to get along with each other and try to figure out the best way to help him deal with Kate's death.
The Wilds: Rachel's protective of her twin sister Nora at times, although they also butt heads.
In the Wishbone episode "The Hunchdog of Notre Dame," Sam sees a teammate being picked on, so she takes him under her wing and teaches him to play better.
Justin, from Wizards of Waverly Place, always fixes Alex's mistakes and saves her from impending doom. She even admits that she always expects him to do so.
Women's Murder Club: Jacobi is fiercely protective of Lindsay, with one episode revealing that all the men who want to ask Lindsay out are forced to talk to Jacobi first for his okay. When he suspects that Tom and Lindsay have slept together, Jacobi tells him to stay away from her so that she won't get hurt again.
In Wonderfalls, much though Jaye finds her family irritating, she has a very strong Little Sister Instinct. In one episode, after a guy punches her brother (played by the rather tall Lee Pace), Jaye (played by the decidedly smaller Caroline Dhavernas) manages to lay out the guy with a single punch.
Jaye: You don't screw with my family.
Bill Scully Jr. of The X-Files has a Big Brother Instinct for his youngest sister Dana, though he can be a jerk about it and doesn't always bother to get all the facts before lashing out at people he sees have "wronged" her...like Mulder. Poor Mulder. (Though, given that the other Scully sister, Melissa, was murdered by someone gunning for Dana because of the life Mulder has drawn Dana into, it's understandable.)
. Indeed, this is one of many examples of Stewart only getting involved in situations in order to defend Colbert, ranging from comedic examples (assisting Colbert in his dance-off with O'Brien