The Battle Nexus
A warrior who comes to Earth to challenge Leo to mortal combat.
- All There in the Script: Concept materials, as well as his action figure, call him "Ue-Sama".
- Antagonistic Offspring: The son of the Daimyo.
- Artificial Limbs: Specifically, his left hand.
- Bitch in Sheep's Clothing: In his second appearance. He acts friendly to the Turtles and claims to be regretful of his actions toward them, but it's soon made clear he hasn't changed one bit; he's conspiring to murder his own father to steal his War Staff, and goes so far as to shoot Leo with a poison dart out of petty spite for losing to him.
- Combat Pragmatist: Best shown in his debut episode. The Ultimate Ninja is more than happy to comply with the rules of combat that benefit him, such as excluding Leo's family from the fight, but the minute he's losing, he's perfectly willing to cheat and do whatever it takes to win.
- Even Evil Can Be Loved: Despite his trying to murder his own father to gain power and the War Staff, the Daimyo still loves the Ultimate Ninja and deeply mourns his disappearance, falling into a depression.
- Even Evil Has Loved Ones: At the last minute, disagrees with Drako's plan to kill the Daimyo because some part of him does actually love his father.
- Evil Is Petty: Shooting Leo with a poison dart has nothing to do with his plan to obtain the War Staff and take over the Battle Nexus. He does it purely out of spite and wounded pride for Leo defeating him in their duel.
- Everyone Calls Him "Barkeep": This guy is never identified by name, except as Drako when he merges with him in the third season. His action figure and casting sheets state his true name is Ue-Sama.
- Fusion Dance: With Drako during the third season.
- Meaningful Rename: The Ultimate Ninja is what he calls himself after he believe he's defeated Leonardo.
- Redemption Earns Life: His disagreement with Drako gets him killed as it causes him to lose the War Staff and the Time Scepter, and the Time Scepter turns him to dust. But since there was some potential for good in him, Lord Simultaneous brought him back as a child.
- Small Name, Big Ego: While he's a skilled fighter, his arrogance far outstrips his ability to back it up.
- Sore Loser: Attempts to kill Leonardo after being officially defeated.
- Taken for Granite / Literally Shattered Lives: This is how he initially dies after "Same As It Never Was" and "The Real World", but he's brought back to life as a child; Drako stays dead.
- Party Scattering: He and Drako as Ultimate Drako are the ones responsible for sending Donatello to the infamous "Same As It Never Was" universe with the Shredder ruling all, while Leo winds with Usagi Yojimbo.
- Raise Him Right This Time: After he is killed Lord Simultaneous revives him as a child. It's implied the Daimyo will do this.
- The Unfavorite: In a sense. He's very pissed off that his father shows others more respect than him.
- Used to Be a Sweet Kid: When revived as a child, we see he was a much nicer person in his youth.
- Walking Armory: Swords, Wolverine Claws, chain and sickle, shuriken, blinding dustthe works.
- Voiced by: Marc Thompson
Ruler of the Battle Nexus and The Ultimate Ninja's father.
- Authority Equals Asskicking: Even without his War Staff, he cut a dragon conjured by his son in half.
- Everyone Calls Him "Barkeep": His true name is never identified.
- Gentle Giant: Sometimes, given his size.
- The Good King
- Long-Lived: We don't know how old he is but he's made out to be ancient, probably the oldest character in the series next to Lord Simultaneous.
- Reasonable Authority Figure: He's the fair and noble ruler of the Battle Nexus. That goes out the window come Season 3, due to bitterness over the loss of his son; when Leo approaches him for help getting back home, the Daimyo instead blames him and his family for his son's disappearance and tries to have him imprisoned forever.
- Sanity Slippage: In the third season, it is clear he has not taken the loss of his son very well.
- Voiced by: Marc Thompson
A Battle Nexus Championship contestant who was defeated by Splinter years ago.
- Arc Villain: For the Battle Nexus arc.
- A Dog Named "Dog": He's a red dragon named Drako.
- Eviler Than Thou: To the Ultimate Ninja when the two came to blows. Turns out while both intended to steal the War Staff, only Drako actually studied how to use it.
- Fusion Dance: Merges with the Daimyo's son in Season 3.
- Hate Sink: Blatantly cheats, resorts to murder upon losing, betrays his partner in crime, and is generally antagonistic toward everyone. Lord Simultaneous doesn't even restore him to life after bringing the Ultimate Ninja back.
- Killed Off for Real: Petrified and destroyed two episodes after scattering the clan.
- Our Dragons Are Different
- Party Scattering: He and the Ultimate Ninja as Ultimate Drako are the ones responsible for sending Donatello to the infamous "Same As It Never Was" universe with the Shredder ruling all, while Leo winds with Usagi Yojimbo.
- Sore Loser: Attempts to have Splinter killed after having lost the Battle Nexus Tournament.
- Taken for Granite / Literally Shattered Lives: This is how Drako finally meets his end after he scatters the Hamato Clan (one of whom, Donatello, gets to witness what will happen should main Big Bad Ch'rell/The Shredder prevail) and is confronted for it. The Ultimate Ninja is brought back to life, but Drako isn't.
- Voiced by: Ted Lewis
A Battle Nexus Championship contestant with an animus towards Michelangelo.
- Ambiguously Evil: While he eventually tries to kill Michelangelo for purely selfish reasons, he also formed part of Traximus' rebel army, which makes it rather hard to get a sense of him.
- Sdrawkcab Name: The character is meant to be a homage to the Hulk.
- Sore Loser: Although he has a point about only losing on a technicality, it eventually becomes clear that he doesn't really give a damn about the Battle Nexus Championship or its rules.
- Super Mode: Inverted, more or less, as he spends way more time in his hulked-out form than he does in his smaller state.
The Battle Nexus: Video Game-Only Characters
- Voiced by: Jason Griffith
- Canon Foreigner: One of the most significant additions Battle Nexus.
- High-Altitude Battle: The second battle against him takes place on a glowing platform suspended in mid-air. Incidentally, this level is also titled 'Air'.
- Meaningful Name: A pretty obvious. A guy wielding a scythe whose name sounds like the word 'slasher'.
- Noble Demon
- Recurring Boss: Slashuur is fought twice each in Battle Nexus, and can optionally be fought a third time in Tournament Mode.
- The Reveal: He is actually an Utrom wearing Powered Armor, much like The Shredder/Ch'rell.
- Secret Character: You can unlock him as a Playable Character.
- Sinister Scythe: His Weapon of Choice.