How did magneto become a villain?

Answer 1

First, he used his powers for good with Professor X. He always thought mutants and humans could never get along. He thought mutants should rule over humans. One day, Professor X and him had a big argument. Then he flew away and next thing you know, he's evil!

Answer 2

Mutants are born. These so called "mutants" are born with an X-gene. This activated gene grants these "mutants" special abilities or powers, as you will. There ARE ways to activate the X-gene, but that usually has disastrous consequences and shouldn't be forced. Some mutants are born with their X-gene active, but most of them will become active during puberty or during times of high emotional stress. Some never activate at all, though this is rare for the most powerful of the mutants, Omega level, though them in and of themselves are a rarity by far.

Answer 3

He is a mutant. Therefore his powers mutated in his body and they manifested at puberty.

Answer 4

The X-Men are mutants, humans born with an "X gene" which activates at puberty giving them special powers.