He possesses a third eyelid, called a nictating membrane, which all Alligators and relatives have so that they can see underwater. Like Raph, Leatherhead has a high temper which can be used to make him stronger, in the right way, but it can leave devastating results as it causes him to go into an uncontrollable amount of rage, endangering anyone, even those he cares about. He seems to have an unbreakable amount of willpower as he would never give into the Kraang no matter what they did. Leatherhead is very intelligent as it seems his time with the Kraang enabled him to gain knowledge and learn what he can about them.
His tough, armored hide is extremely resistant to attacks, even from Kraang laser blasts.
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He's immensely large and powerful using his tail, claws, and crushing bite to full effect in combat. Like the majority of the mutants, Leatherhead has the abilities to speak and reason. This third lid locks in place whenever Leatherhead goes into a rage. He possesses a third eyelid, which all Alligators have so that they can see underwater. He has a tough, armored hide is extremely resistant to attacks, even from Kraang laser blasts. He has an immensely large, has a long tail, sharp claws and large mouth like all alligators do. He resembles a gator ( or more accurately a crocodile) with humanoid arms, legs and the ability to speak and reason. Leatherhead is now trapped in Dimension X.
He beats up Traag and goes through the portal to give the Turtles time to escape. He is used as a distraction to allow the gang to get to the top of the TCRI building. In TCRI: Leatherhead is awoken to grab Donnie in the face again. He snaps out of it and tells the gang all he remembers about the Kraang and the Portal. He destroys all of the Kraang in order to keep the fact that the Turtles possess the power cell a secret. He entrusts the power cell to Mikey, his first friend and goes out to fight the attacking Kraang and give the turtles time to escape. The other Turtles arrive, thinking Leatherhead will hurt Mikey, but Leatherhead pleads with them and explains his origins. Mikey finds Leatherhead at his own lair in an abandoned subway car. Mikey immediately rushes out to find him. Splinter is able to defeat him and drive him off. When the other Turtles recover the power cell and Leatherhead sees what they have done he loses control again and attacks all of the turtles,even Mikey. Leatherhead attacks the Turtles repeatedly, but Mikey is able to befriend him and earn his trust.
Leatherhead is rendered unconscious and Mikey convinces the others to take him back to the lair. Michelangelo leads the charge to help him. Season 1 It Came From The Depths: The Turtles find Leatherhead in pitched battle with a squad of Kraang. The Kraang had been hunting Leatherhead and the power cell for six months when the turtles found him. Without this cell the Kraang cannot pass between Earth's dimension and their own. He escaped his captivity and returned to Earth using the Kraang's dimensional portal, at the same time stealing the Power Cell that ran it. They performed horrifying experiments on him but, through all of it, they could not break his spirit. This is where the Kraang found him and brought him back to their dimension. As a normal baby Alligator, Leatherhead was raised by a kind Human boy ( whose name remains unknown) until his disapproving parents flushed him down the toilet into the sewers.