The Koopa skeleton holding a farewell note in Hooktail Castle. Koops believes it's his father’s skeleton, though it turns out it's not. It's Kolorado's father.
After defeating Hooktail, she spits out Koops’ real father and they have a heartwarming reunion.
A rather minor one, but still sad. After completing Chapter 1, Mayor Kroop of Petalburg puts in a trouble at the Trouble Center requesting that someone come talk to him (exact words: "Will someone please talk to me? Please?"). Considering it's already a Running Gag that Kroop is a crazy old senior who rambles for so long that those listening to him fall asleep, the trouble, of course, is Played for Laughs, but consider the predicament of many real life seniors who wind up friendless and lonely in their old age, and the event suddenly becomes much sadder. And leads to a Heartwarming Moment when Mario takes the trouble on.
Chapter 2
Beldam abusing Vivian is particularly hard to watch, especially if the player has been bullied or been in an abusive relationship before. What makes it worse is how realistic the whole thing is portrayed, with Beldam constantly insulting and finding new ways of beating her down. Even Goombella is appalled that anyone could be that cruel to their own family member when you tattle Beldam on the field prior to the Shadow Sirens fight.
A particularly hard moment to watch is when Beldam finds the sketch of Mario they were looking for (that she had the entire time), then immediately blames Vivian for "misplacing" it and doesn't care when Vivian attempts to point out she never had it. Then Beldam proceeds to confiscate the necklace Vivian was so infatuated with and demands that she find Mario by herself. THEN, she launches into insulting Vivian again when the latter comes up with a cute nickname and doesn't understand her sister's speech patterns.
Even worse is Vivian just collapsing to the ground crying after Beldam promises to "punish" her for disobedience. She KNOWS what her sister means, but is too terrified to disobey.
The implication of Beldam's "punishments" means she physically abuses her younger sister as well as verbally. Even Marilyn isn't safe from them either!
Chapter 3
Jolene reveals that she was the mysterious X person who helped you discover Grubba's evil secret. Her motivation for this was because her little brother, Mush (aka Prince Mush, the first champion of The Glitz Pit), went into fighting to provide money for his poor family. Then Grubba made him vanish. She just wanted revenge for her brother's disappearance. Thankfully, the Gold Crystal Star brings Mush back, and the siblings are reunited.
Chapter 4
Vivian pulls a Heel–Face Turn during the battle against Doopliss at the end of the chapter. She decides to help Mario because her sisters treat her like dirt and that he was one of the first people who was kind to her.
However, what comes before is one of these for a different reason. After Doopliss exposes who she has been helping, Vivian realizes she has been helping her enemy this whole time and feels like an idiot. She even leaves for a while right before the battle, before she realizes she liked being with Mario way more then she did her sisters.
Also found in Twilight Town, Mario can enter one of the homes to find a mother and her 3 children, all starving because their father has been turned into a pig due to the curse that plagues the town. After asking Mario for some food, the mother is interrupted by the ringing of a bell and gets turned into a pig herself. Two of the children seem quite upset about the situation, while one calmly asks Mario if pigs are a good eat, giving some frightening and sad implications.
When you use Vivian's field ability to eavesdrop on some of the Twilight Town birds, one bird states that her son is getting ready to take his SAT's. Come back later and she reveals the poor kid failed.
Flo: He studied so very hard, and we spent so very much.
After Doopliss steals Mario's identity, try talking to some of the people in town. Most of the reactions will be them praising Mario (actually Doopliss) and having no idea who you are, criticizing your appearance, or freaking out thinking you're some sort of monster. The worst, however, is the mayor, who can be witnessed treating Doopliss-Mario and co to a feast in his house while coldly dismissing you if you talk to him. Come back later, and he not-so-subtly insults you and demands you to get out of his house, which is rather jarring considering how friendly he is otherwise.
Chapter 5
Perhaps the biggest one in the game is Bobbery's letter from his dead wife, Scarlette. When Podley said that his friend's story was a tragic one, he wasn't kidding. Each partner also has their own reactions to hearing that story.
Ms. Mowz: Why do most romances have to end in tragedy? Why?
Even more poignant is how Bobbery himself reacts. He asks if he can have a moment alone and then walks into his bedroom. This is a widowed man mourning his dead wife and asking if he can have a moment to cry alone because he's reading words from the departed love of his life. The fact that it's played so straight, so maturely, is what makes it hit hard. It's not made into a joke like saying that she died blowing up because she's a bomb. It's portrayed as a man realistically grieving his wife, blaming himself, and shutting himself in to become even more miserable as he stews in bitter regret. Bobbery's tale is heartbreaking.
After fighting off a group of ghosts by himself, an injured, presumably dying Bobbery asks Mario to fetch him his bottle of Chuckola Cola, the one he had been saving for him and Scarlette, so that he could savor one final drink before expiring. When you get it for him, the heartbreaking music kicks in as he takes his last drink, then utters how he'll finally be with Scarlette. With his final wish fulfilled, the sea captain dies peacefully... or at least, you think he does, until you realize thathe just fell asleep.
Chapter 6
In the post-Chapter 6 Peach segment, Grodus orders TEC be disconnected after learning the computer's been assisting Peach (and Mario by extension). TEC's is just barely able to say a farewell message to Princess Peach right before he's disconnected.
When you get the Ultra Hammer and Toadette finishes her explanation, she starts feeling sad because that's the last time she'll see Mario, and she's clearly saddened about it. What really hits it is how she runs away as if she were trying not to cry...
Chapter 7
TEC barely manages to survive on backup power and weakly tells Mario how to escape the X-Naut fortress at the cost of his own life.
Also, all the people you have met along your adventure start to cheer you on during the battle. They're on the edge of despair and plunged in darkness, but seeing the Crystal Star show up in their area reminds them of Mario's impact on them in his adventure, and it revitalizes their hope. It definitely reflects on the player too— you've come so far, and seeing all these characters rooting for you and showing the progress you've made, is just amazing. It definitely counts as a Moment of Awesome and a Heartwarming all at once.
An optional sidequest has you delivering a message from the Twilight Town villager Eve to the owner of the Cola bar Podley. The reason? The two were once aspiring stage actors who were madly in love with each other, so much that they were happy despite being dirt poor. Then Eve landed the leading role in a Broadway play, which caused the still undiscovered Podley to feel that he was holding his beloved Eve back and left her so that he wouldn't drag her down. This had the opposite effect, as to Eve, success meant nothing if Podley wasn't by her side, which led her to give up her acting career and start a family. Eve sends Mario to ask Podley how he feels about her. When you do, he'll simply pretend that he never knew an Eve and tell Mario to tell Eve to live in the moment, but as you walk away he mutters to himself "Oh, my dear Eve..."
In general, watching Vivian get bullied by Beldam, especially if the player has experience being bullied by family themselves. No matter what Vivian does, Beldam continues to find ways to beat her down and it shows by how much of a Socially Awkward Hero Vivian is.
