Johan was a vicous young thug who terrorised Christina and Hans. He eventually killed Christina's father, along with his two friends, and framed Hans for the murder. Later, when Frankenstein brought Hans back from the grave (along with Christina who had killed herself in grief), they killed Johan's two friends. Johan, knowing he would be next, fled the town but Christina tracked him down, seduced him and eventually sliced him open with a knife after revealing to him who she really was.