Cerebro detects the presence of an incredibly powerful being outside of the mansion, so the X-Men activate the mansion's defensive measures. The villain is able to break through line after line of defenses, so Professor Xavier informs his students of who the villain is so that they know what they will be fighting. Professor Xavier informs them that it is Cain Marko, his own stepbrother. Professor Xavier tells his X-Men the origin of their two families. After Professor Xavier's father was killed in an accident, Dr. Kurt Marko began courting Charles' mother, and eventually the two married. Sharon dies of a broken heart shortly into the marriage. One day Charles overhears Cain and Dr. Marko talking about inheriting the family fortune. Charles interrupts and a fight breaks out. A fire starts b