The Alter Ego fights you with your own moves. It is a reflection of the Hero made from the random rampant gas that forms around Godville. It becomes something the Hero could have been, with greater strength and powers. Unfortunately, since the hero isn't very bright and doesn't have much potential, the Alter Ego isn't very different from the hero at all, except perhaps being marginally stupider, but that's debatable.
* Will always be slightly stronger and faster
* Its stupidity doesn't always tell it when it dies
* Doesn't have a god
* Its armor and weapons are fake copies of the Hero's
* May be even more stupid than the Hero