villain

1.A wicked or evil person; a scoundrel.
2.A dramatic or fictional character who is typically at odds with the hero.
3.Variant of villein.
4.Something said to be the cause of particular trouble or an evil: poverty, the villain in the increase of crime.
5.Obsolete. A peasant regarded as vile and brutish.

at odds:
In disagreement; in conflict: "The artist and the self-critic . . . are, with a few felicitous exceptions, forever at odds" (Joyce Carol Oates).