Genocide Jack's appearance is nearly identical to Toko Fukawa's, since they share the same body. However, some features differ: her irises expand and become red, and she gains an abnormally large tongue over a mouthful of sharp teeth. She also tends to make wild, exaggerated expressions.
Despite being a bloodthirsty and potentially very dangerous serial killer, Genocide Jack is mostly portrayed as comic relief in the Danganronpa series. She obsesses over Byakuya Togami.