Chizome Akaguro (赤あか黒ぐろ血ち染ぞめ, Akaguro Chizome?), also known as Hero Killer: Stain (ヒーロー殺ごろしステイン, Hīrō Goroshi Sutein?), and formerly the vigilante Stendhal (スタンダール, Sutandāru?), is a villain and ex-vigilante that is notorious for having killed many Pro Heroes. He is the main antagonist in the titular Vs. Hero Killer Arc.

Chizome was imprisoned in Tartarus, but has escaped alongside most of the other inmates after All For One's attack on the prison.[3]