Krang

Krang is an extremely intelligent warlord from Dimension X. He somehow took command of an army of Rock Soldiers under the leadership of General Traag, and stole the Technodrome, a powerful battle fortress, from its creator Drakus. Something then happened, that caused Krang to be stripped of his body and confined to a brain-like form, and to be exiled from Dimension X to Earth, along with his army and the Technodrome.

While on Earth, Krang allied himself with the Shredder, who, along with his robotic Foot Soldier army, moved into the Technodrome. In exchange, the Shredder had to design and build a new body for Krang, a human-shaped exo-suit.