Tetsuo (鉄雄), full name Tetsuo Shima (島 鉄雄), is the main antagonist of Akira. He evolves from Kaneda's best friend and gang member to his nemesis. He is involved in an accident at the very beginning of the story, which causes him to display immense psychic powers. He is soon recruited by the Colonel and became a test subject known as No.41 (41号).