Kraang is a character loosely based on the Utrom race from the original comic, and is an ally of Shredder. In Dimension X he was a powerful dictator/warlord who led brutal campaigns of Rock Soldiers, with fanatically loyal-to-Krang General Traag as his direct subordinate. He also took the completed Technodrome, a powerful mobile battle fortress, and banished Drakus who helped Kraang build it to Earth.
One day, an unexplained, bizarre incident occurred that caused Krang to be stripped of his body and reduced to a brain-like form, also resulting in his exile from Dimension X to Earth. After he was banished from his original dimension, along with his operative fortress the Technodrome, they somehow found their way into the hands of Oroku Saki. Kraang allied himself with the Shredder, who, along with his robotic Foot Soldier army, moved into the Technodrome.