Why did Jean turn evil?

Why did Jean turn evil? In the comics, Jean Grey merges with a cosmic entity known as the “Phoenix force” but struggles to control her newfound power. A villain called Mastermind hypnotizes and enslaves Jean, manipulating her mind and body, even dictating what she wears.

In the comics, Jean Grey merges with a cosmic entity known as the “Phoenix force” but struggles to control her newfound power. A villain called Mastermind hypnotizes and enslaves Jean, manipulating her mind and body, even dictating what she wears.