The Touch of Divinity
I am Sin, Thief of Virtue, and it is mine to take what I will from the defeated, to make a gift of it to the victorious. Alas, your mortal frame cannot withstand the unfettered fire of deism.
Once you defeat your first god - usually, Tukohama in early Act 6 - you'll gain access to the Pantheon system, yet another way to customize your character. Unlike most of the character customization methods, though, you can change Pantheon powers at-will while in town and are not locked-in to any.
Each god you defeat will unlock a new power on your Pantheon pane, which you can view by pressing [y]. Initially, these powers will give one minor effect, but later on you'll be able to upgrade them.
Each god is classified as "minor" (a boss within an act) or "major" (act end bosses). You can have one power from each set active: one major, and one minor.