Ben 10: Gods and Monsters

The Ben 10 franchise (Original, Alien Force, Ultimate Alien, Omniverse) is a long-running franchise full of interesting characters, but what if certain aspects changed it a little?

What if there were villains that included a sadistic Mad Scientist who became a demon warrior, a monstrous tyrant based on a popular anime villain, and even a version of Satan himself?

Characters:

Ben and co.:
 * Ben
 * Gwen (discovers a brand new merged form in Alien Force while fighting the aforementioned tyrant)
 * Kevin