15Professor X Had An Affair And Neglected His Son
Whenever he is not sending teenagers to fight for the sake of the world, Professor X is a pretty decent guy. However, for someone with so much wisdom, he's made some big mistakes in the past.
One of his biggest errors in judgment was sleeping with his former patient, Gabrielle
This decision would later come back to haunt him in the form of his son David Heller, aka Legion. As one of the most powerful mutants in existence, Legion possesses several powers including telepathy, telekinesis and reality warping. What’s worse is that Legion’s powers are highly unstable due to his multiple personalities.
This combination of neglect and instability leads Legion down a path of destruction resulting in many casualties. Even though Professor X was not aware of who Legion was until after the events happened, he still bears responsibility for his son’s actions.