Guren Nash/Tenkai Knight Bravenwolf (Guren Ogami)
Voiced by: Johnny Yong Bosch (English), Meguru Takahashi (Japanese)
- All-Loving Hero: Has shades of this, what with being a Kind Hearted Cat Lover and kid who thinks recycling is good for everybody.
- Animal Motifs: In Titan mode, his chest plate becomes the head of a dragon.
- Anime Hair: Guren's hair is red in the front and black in the back.
- Berserk Button: The other knights have trouble keeping up with Guren's during his assault on Vilius's forces after his father gets brickified.
- Beware the Nice Ones: Guren is one of the sweetest, most polite, helpful kids around. But don't get on his bad side.
- Chronic Hero Syndrome
- Dating Catwoman: Downplayed, he a lot nicer to Beni even after learning she is Venetta though that doesn't stop Ceylan from calling her his girlfriend.
- Expy: That hair of his is VERY similar to Atlas.
- Good Is Not Soft
- The Hero: He's the real star of this show; he leads the group and the story is generally told from his perspective.
- Heroes Prefer Swords: Guren receives a sword when he transforms into Bravenwolf.
- The Idealist
- Missing Mom: She's dead.
- New Transfer Student: Guren transfers to a new school in the very first episode of the series.
- Nice Guy
- Playing with Fire: Gets this power with the upgrade in episode 27.
- Red Oni, Blue Oni: While all four boys have red oni and blue oni traits, it's more obvious with him and Ceylan/Tributon. Although it is color inverted, the red colored Bravenwolf is the blue to blue Tributon's red.
- When You Coming Home, Dad?: His father is frequently busy. There are days where he doesn't even come home at all, even though it's not like he works outside of town. This weighs on Guren, naturally.
Ceylan Jones/Tenkai Knight Tributon (Seiran Washizaki)
- An Ice Person: Gets this power with the upgrade in episode 27.
- Animal Motifs: In Titan mode, his chest plate becomes the head of a bird.
- Book Dumb: Ceylan isn't very interested in studying.
- Class Clown: In fact, this is how and why Guren met him and became fast friends with him in the first place. Having said, Ceylan is in fact a very cautious soul, and quick to point out when something doesn't seem entirely kosher to him.
- The Cynic: In contrast to Guren's Wide-Eyed Idealist.
- Deadpan Snarker: Ceylan, definitely. About half of his lines are said in a somewhat sarcastic manner.
- Goggles Do Nothing: Wears goggles for style.
- The Lancer: He's the first to meet and become friends with Guren, and therefore he's closest to him. His jokester tendencies also contrast with Guren's more pondered nature.
- Sad Clown: Ceylan appears to suffer from self worth issues that have made him consider leaving the team on more than one occasion. Nevertheless he's appointed himself the team's "funny-man", trying his best to appear the carefree joker when deep down, he's anything but carefree.
- Red Oni, Blue Oni: Color inverted. Tributon is blue yet is the red to the red Bravenwolf's blue.
- Refusal of the Call: Ceylan is at first overwhelmed by the responsibility of the universe hanging over his head and promptly decides to not continue fighting. He changes his mind by the end of the episode.
- You Gotta Have Blue Hair: Ceylan's a solid blue.
Chooki Mason/Tenkai Knight Lydendor (Chuuki Hachisuka)
- The Ace: Still a Nice Guy though.
- Animal Motifs: In Titan mode, his chest plate becomes the head of a reptile.
- Born Lucky: Chooki is so mind-bogglingly lucky that it defies logic. He wins every game he plays. Ceylan attributes it to supernatural powers.
- Child Prodigy: In the field of sports.
- Lovable Jock: He's awesome at sports, which he frequently uses as analogy for all sorts of situations.
- Shock and Awe: Gets this power with the upgrade in episode 27.
- The Smart Guy
- Smart People Play Chess: One episode shows him beating a much older man at chess.
- Sore Loser: Downplayed. He doesn't behave inelegantly, but he still takes it pretty hard when someone beats him at some sport, and is prone to brooding about it.
- The Strategist: Chooki often comes up with the battle plans.
- Throwing Your Shield Always Works: In his Titan mode, Lydendor's bladed shield becomes his main weapon over his flail.
- Wise Beyond His Years: Is more level-headed than the other boys.
Toxsa Dalton/Tenkai Knight Valorn (Takusa Kameyama)
Voiced by: Ben Diskin (English), Maki Mizuma (Japanese)
- Animal Motifs: In Titan mode, his chest plate becomes the head of a turtle. The armor on his back also resembles a turtle shell.
- Ascended Fanboy: Toxsa has always been into video games, so becoming a Tenkai Knight was easier for him to get a handle on.
- Big Eater: Not really given much focus, but Toxsa eats a lot.
- The Big Guy: Valorn is the bulkiest of the Tenkai Knights. Combined with Toxsa's personality, it makes him something of a musclehead. Toxsa, ironically, is the tiniest of the guys.
- Blade on a Stick: Weapon of choice as Valorn.
- Bratty Half-Pint: Shortest and most obnoxious of the four.
- Cloud Cuckoolander: Toxsa is definitely the most cooky of all the boys.
- Dishing Out Dirt: Gets this power with the upgrade in episode 27.
- Geeky Analogy: Often references things he did in a video game to what's happening at the moment.
- Hot-Blooded: All the boys are a little hot-blooded to a degree. But Toxsa is definitely the most hot-blooded of them all.
- Leeroy Jenkins: At times.
- Nonstandard Character Design: Although his smaller size is justified given that he's a year younger than the others, Toxsa's eyes are much larger and rounder while his irises are much smaller.
Voiced by: Crispin Freeman (English), Yosuke Akimoto (1st voice), Nobuo Tobita (2nd voice) (Japanese)
- All According to Plan: Says it word for word after his defeat in episode 13.
- Authority Equals Asskicking: A completely Justified Trope.
- Back from the Dead: Vilius is resurrected when he dies and proceeds to revive his dead henchmen afterwards.
- Big Bad: Vilius started the war for Quarton and seeks the Tenkai Dragon. While Gen had plans to overthrow him, Vilius sees through this and turns the tables against him.
- Big "NO!": When the Tenkai Knights (plus Gen) defeat him in their new Phoenix Mode.
- Card-Carrying Villain
- The Corrupter: A rather literal case, he has the ability to turn Corekai into the Corrupted.
- Enemy Mine: Averted in the Beast King arc. Despite being in the same situation as the Tenkai Knights, he really doesn't wish to collaborate with them against Scorpidon and Orengor. Though he does note at one point, "It's hard to decide who to root for".
- Evil Overlord
- Evil Wears Black: A common trait found in the Corrupted forces.
- Fallen Hero: According to the official website, Vilius was once part of the Tenkai Knights himself, a highly respected part of the Corekai, until his greed got the better of him and he was cast out. It was then that he decided to overthrow the Corekai and eventually rule the entire universe.
Voiced by: Steve Blum (English), Hisao Ogawa (Japanese)
- Animal Motif: Granox's design is meant to resemble a rhinoceros.
- The Brute: Not known for his strategic genius.
- Dirty Coward: One thing he and Slyger have in common. When things get really bad, he gets going.
- Evil Sounds Deep: A more guttural voice.
- Glass Cannon: Granox seems invincible at first, but he goes down just as easy as Slyger once he's hit.
- It Has Been an Honor: Presumably attempts to tell this to Slyger, knowing that they might lose to Chooki and Toksa in their final showdown. Slyger was too full of himself to let him finish, though.
Voiced by: Crispin Freeman (English), Atsushi Imaruoka (Japanese)
- Animal Motif: While his speech and mannerisms seem to evoke serpents, Slyger's large claws and Titan Mode goes with a cat/panther motif.
- Blood Knight: Much more eager to cause destruction.
- Dirty Coward: Same as Granox.
Gen Kurai/Tenkai Knight Dromus (Gen Inukai)
- Adorkable: Demonstrated when he's reluctantly covering for the knights when Toxsa is brickified by distracting Wakamei.
- Animal Motifs: Since Dromus is Bravenwolf except black, he also gets a dragon motif.
- Blow You Away: Gains wind powers from his Elemental form.
- The Dragon
- Emo Teen: Gen has the appearance (although not the personality) of this. Lampshaded by Toxsa himself.
- Evil Counterpart: Dromus serves this to Bravenwolf, said same goes to Gen to Guren and in addition to being The Rival.
- Expy: Gen strongly resembles Sasuke with the hairstyle, clothing, personality, emo appearance (this is lampshaded by Toxsa himself), and even share the same voice actor, Yuri Lowenthal. He also works with Vilius under the guise of Tenkai Knight Dromus; and serves as The Rival and Evil Counterpart to Guren.
- Heel–Face Turn
- Perpetual Frowner: Even after he joins the Knights, he does little smiling.
- The Quiet One: Gen doesn't like to socialize with other people. This is because he is working with Vilius and prefers to work alone in secret.
- Sixth Ranger: Joins the Tenkai Knights in "A New Knight" when he realizes that destroying both worlds isn't what he really wanted.
- The Starscream: Gen's not even being subtle around Vilius about the fact that he's just using him to get the Tenkai Dragon's power for himself.
- The Stoic: He isn't really that emotional.
- Straw Nihilist: Whatever happened to his family caused Gen to become this and seek to destroy all worlds. Guren calls out how pathetic he is for it and makes Gen start to realize this.
- Used to Be a Sweet Kid: As seen in a flashback, Gen was able to smile once.
Beni/Tenkai Knight Venetta
- Action Girl: As Venetta.
- Animal Motifs: Look at Venetta's back and you may notice there's a spider there. The green dots all over her body are also meant to resemble spider eyes.
- Cute and Psycho: Beni likes flirting with Guren and planning the utter annihilation of her own species, all in the same sentence.
- Dark Action Girl: Beni becomes one when she is Venetta.
- Dark Chick
- Femme Fatale
- Heel–Face Turn
- Lady of War: Venetta certainly is one of these.
- Pink Means Feminine: Ceylan openly assumes that the newest Tenkai Knight must be a girl due to "Venetta" wearing almost completely pink armor. Chooki calls him out on his bias and tells him not to make assumptions. Turns out, Ceylan was right.
- Women Are Wiser: Seems to have this attitude since many of her insults involve things like "he's just a typical boy".
- Cool Old Guy
- Eccentric Mentor: Loves espousing weird Ice Cream Koans.
- The Mentor: To the boys, teaching them about Quarton, the Tenkai Knights, and their enemies.
- Mysterious Past: He has a Core similar to the boy's, he often vaguely alludes to his past but never explains himself fully.
- Retired Badass: Once implied to Guren that he used to go to Quarton.
Mr. Nash (Mr. Ogami)
- Parental Neglect: While he does spend most of his time working, he really does care about Guren.
- Workaholic: Instead of seemingly being distant from his son, he acts like a pretty cool dad onscreen and hasn't been seen actually working yet, but it's said that he spent the last two years working instead of paying any attention to his son and has had moved do to work three times during that period.
Wakamei Dalton (Wakame Kameyama)
- Cool Big Sis: Despite their differences, Wakamei does her best to be one for Toxsa.
- Double Standard: Abuse, Female on Male: She beats Toxsa whenever he annoys her (that's pretty often).
- Hot-Blooded: Like brother like sister.
- Secret Secret-Keeper: She eventually finds out about Quarton, the Knights and everything. She pretends not to know to humor Toxsa.
- Tough Love: Wakamei's a big fan of this.
- Cannot Tell a Joke: Or trash-talk.
- Hero-Worshipper: Beag practically worships the ground the Tenkai Knight's walk on and often marvels at every thing they say and do, not knowing they're four pre-teen boys from earth. He's also usually the one explaining to them how things work on Quarton and what's going on at the moment.
- Honorary True Companion
- Large Ham: Has a rather grandiose style and tone of speech.
- Sixth Ranger
The Guardians (Boreas, Eurus, Zephyrus, and Notus)
Voiced by: Steve Blum (Boreas), Kyle Hebert (Eurus and Notus), Matthew Mercer (Zephyrus) (English), Shigenori Soya (Boreas), Hideyuki Umezu (Eurus), Junichi Yanigata (Zephyrus), Michiko Neya (Notus) (Japanese)
- Apologetic Attacker: Notus while fighting the Knights under Vilius' control.
- Balance Between Good and Evil: Their task is to oversee this.
- Big Good: They watch over the peace in Quarton.
- Bigger Bad: Eurus served this in the first half before realizing he let Vilius go to far.
- Brainwashed and Crazy: By Vilius in the second half of the show.
- Color-Coded for Your Convenience: Blue, red, green, and yellow, respectively. No relation to the Knights, tho.
- Dub Name Change: Minor example, but, for some reason, Zephyrus and Notus' names are reversed from the Japanese version.
- Evil Makeover: Their silver armor becomes black under Vilius' control.
- Greek Mythology: Named and styled after the Anemoi, Greek deities of the wind.
- Hufflepuff House: Zephyrus and Notus don't get as much focus as the other two.
- Mentor Archetype: In the first half of the show, Boreas directly guides and advises the Tenkai Knights.
- One-Winged Angel: They all have the ability to fuse with multiple robots to become giant beasts. This is called Mega Fusion.
- She's a Man in Japan: Notus is female in the Japanese version.
Kiro Mason (Kiiro Hachisuka)
Voiced by: Laura Bailey (English), Maasa Kobayashi (Japanese)
- Annoying Younger Sibling: She's Chooki's cousin, but otherwise behaves like the essence of this trope, constantly nagging him to let her have fun and crying loudly when she can't.
- Chekhov's Gunman: Is the one to finally give the Knights the Tenkai Stone.
- Girls Love Stuffed Animals: Has a rabbit or dog-looking thing named Sandy that she carries around at all times.
- Morality Pet: Makes Beni take a definite turn for the better.
- Strong Family Resemblance: Blond hair, green eyes, and same facial structure as Chooki. Lampshaded by the others.
- Everything's Better with Monkeys: If the name didn't clue you in.
- Informed Species: His name evokes orangutans, and while he is red, he is otherwise too hairless and has too light skin to really be one.
- Screwy Squirrel: While he claims to be doing the things he does to humor Scorpidon, his glee while doing them suggests otherwise.
- Small, Annoying Creature: His nonsense really grates on the protagonists' nerves.