Plumbers of Bellwood
Benjamin Kirby "Ben" Tennyson/Ben 10
- Character Catchphrase: Like in previous two series, Ben's catchphrase is still "It's hero time!"
- Character Development: His characterisation evolves from being a Jerkass to a badass during the series.
- Half-Human Hybrid: Subverted, he does not have the genetic powers from his Anodite grandmother but he manages to turn into an Anodite thanks to Gwen injecting her Anodite DNA into his Deltatrix.
- Happily Married: In the flashforwards series finale "Epilogue", he and Julie are now married.
- The Leader: He is the Magister from Plumbers of Bellwood.
- Transformation Trinket:
- The Omnitrix 2.0. (until the beginning of season three)
- Season three onwards: The Deltatrix.
- Official Couple:
- Previously with Julie and with Kai until season four.
- Since the fifth season finale: With Julie.
- Retired Badass: In the series finale.
Kevin Ethan Levin
- Half-Human Hybrid: Osmonian-human hybrid, since his deceased father was an Osmonian-human hybrid himself. In fact, Osmonian-human hybrids are sometimes referred to as "mutants".
- Important Haircut: He cuts his shoulder length hair short in the first episode since Dark Endgame.
- Took a Level in Kindness: He's much kinder and less of a jerk than he was in Alien Force and Ultimate Alien. This is due to the fact that he's fully redeemed and he's more proud as a hero than a villain.
Gwendolyn Catherine Jane "Gwen" Tennyson/Dark Gwen
- Action Girl: She's a black belt and The Arch Mage, thanks to being an Anodite.
- Brainwashed and Crazy: As Dark Gwen.
- Expy: Her Dark Gwen personage is Jean Grey/Phoenix, Rachel Roth/Dark Raven, Hotaru Tomoe/Mistress 9 and Willow Rosenberg/Dark Willow combined.
- Face–Heel Turn: After becoming Dark Gwen in season one, but gets better in the conclusion for the "Dark Gwen" story arc.
- Girly Girl with a Tomboy Streak: Though still a girly girl, Gwen is also an experienced fighter, since she learned karate sometime before the beginning of Alien Force.
- Half-Human Hybrid: Is an Anodite-human hybrid, since she gained her alien powers from her grandmother Verdona.
- Light Feminine and Dark Feminine: As a villainess, Dark Feminine to Hope's Light Feminine.
- Official Couple: With Kevin until season three when they amicably break up. They eventually restart their relationship during the final story arc.
- Retired Badass: In the series finale.
- Tomboy and Girly Girl: Formerly a tomboy, girly girl to Kai's tomboy.
Charlotte Hope Tennyson Saucerer/ Charmcaster
- The Atoner: She regrets her villainous persona as Charmcaster after realising that her uncle killed her father. This is also her reason to join the team in order to atone for her sins, which is the similar case for Kevin when he joined Ben and Gwen in Alien Force.
- Good Feels Good: She's more happier as a heroine than as a villainess.
- Forced into Evil: It's revealed in the episode "There's No Business Like Slow Business", that after losing her father as a girl along with her mother missing, Hope was brought up by her uncle Hex and that he was very abusive towards her, hence she was forced to become Charmcaster.
- High-Heel–Face Turn: Finally redeems herself in Dark Endgame.
- Older Than They Look: Despite looking like the same apparent age as Ben, Gwen and Kevin, she's actually 23 at the start.
- Took a Level in Kindness: After her High-Heel–Face Turn, she becomes a very kind person, having renounced her former past as villainess.
- You Killed My Father: She realises that her uncle Hex is responsible for killing her father.
Cooper Daniels
- Expy: His ability to build gadgets for the Plumbers of Bellwood are a reminiscent of Billy Cranston from Mighty Morphin' Power Rangers.
- Genius Bruiser: Though a strong, muscular man like in Ultimate Alien, he's also an intellectual like his ability to build gadgets.
Kendra "Kai" Green
- Amicable Exes / Better as Friends: With Ben, from season four onwards.
- Badass Native: She's of Navajo descent.
- Expy: Her abilities to transform into a werewolf are a reminiscent of Wolfsbane from New Mutants, especially that her form is bipedal.
- Magical Native American: Averted.
- Official Couple: With Ben until season four.
- Tomboy and Girly Girl: Tomboy to Gwen's girly girl.
- Wolf Man: Her form is a feminine variant of this.
Rook Blonko
- Put on a Bus: He and Ester leave the team in the beginning of season five.
- The Bus Came Back: They temporarily rejoin the team for the last twelve episodes of season five along with the series finale.
- The Quiet One: Several of his appearances involve him speaking in one line or two. He has no episodes in which he doesn't speak at all.
Ester Waterfalls
- Put on a Bus: She and Rook leave the team in the beginning of season five.
- The Bus Came Back: They temporarily rejoin the team for the last twelve episodes of season five along with the series finale.
- The Quiet One: Several of her appearance involve her speaking in one line or two. She has no episodes in which she doesn't speak at all.
Pierce Wheels
- Burger Fool: He briefly works at the Hamburger Barn in "Mystery Meat".
- Half-Human Hybrid: He's a Porcupinian-human hybrid as his biological father was an alien Plumber who died when he was little. Like Ester, his half-sister Helen and Manny, he stays looking like his alien form.
- Spared by the Adaptation: His death from "The Purge" is retconned in Dark Endgame, in which his death was faked and that he was brainwashed into evil.
Julie Yamamoto
- Amicable Exes: With Ben until season five. They moved on from their breakup that happened in Dark Endgame until they reconcile in the fifth season finale.
- Old Shame: In-Universe example. According to Word of God, she now regrets joining the Flame Keepers' Circle as she blamed herself for several reasons: Not believing Ben, staying that she had no regrets in joining the cult even after realising that it was an evil and her Never My Fault attitude.
- Tomboy with a Girly Streak: She's athletic but is also feminine.
Lucas Johnson
Tara Vasquez
- Half-Human Hybrid: She's an Uxorite-human hybrid and also her grandmother is none other than Xylene. Like Gwen and Alan, she can switch between her human and alien forms.
- Twofer Token Minority: A threefer example, she is of Mexican (from her father's side) and Russian-Jewish (from her mother's side) descent but she's also an alien-human hybrid, according to
Word of God.
Allies
Maxwell "Max" Tennyson
- Big Good: Even after promoting Ben to becoming leader of the Plumbers of Bellwood.
- Killed Off for Real: He dies in the end of "Going Back in Time".
Azmuth
- Killed Off for Real: He dies in the prelude Dark Endgame.
Shadow Alliance of Evil
- Evil Counterpart: To the Plumbers.
Martin Price/The Leader
- Big Bad: Of the whole series
- Greater-Scope Villain: When The Dragon of each season confronts the Plumbers of Bellwood, mainly in the finale of each season (except season one).
- Expy: Word of God has stated that he is loosely based on Jedekiah Price.
Minor villains
Khyber and Metalhound
- Gender Flip: After making an appearance in Plumbers of Bellwood, it was revealed in Omniverse that Khyber's dog is female. In fact, the episode the dog appeared in, was written before the reveal in Omniverse, so the dog in this continuity remains male and is called Metalhound (Still his name was given before his main counterpart was given the name Zed in a later episode of Omniverse).
- Villain of the Week: They serve as the main antagonists of "Parallel Lines" and "Finding Ben".
Harold Saucerer / Hex
- Abusive Uncle: Towards Hope.
- Asshole Victim: He showed no sign of remorse towards his actions and gets killed by Ben and Gwen in the season three finale.
- Big Bad: Of season three.
Legacy Plumbers
Tyler and Jade Tennyson
- Expy: According to the creator, they're the main universe counterparts of Ben and Kai's children in the future depicted in The Original Series, Ken and Gwen Tennyson.
