Fall of the Righteous Eternal

With the belief that he was going to die young, Dan did many dangerous things in his youth - to the point where he sought out the biggest dangers to attempt to get the thrill of excitement.

One day, he performed a ritual that summoned an evil god. The Evil God offered Dan a deal:

In exchange for one power of his choosing, the Evil God would be owed a favour.

Dan, being the risk taker he was, accepted. Immortality, he said, not expecting it to actually be granted.

This is the story of how, after years of saving the world, Dan fell from the righteous path.