If I have a DFC (Ulrich of the Krallenhorde//Ulrich, Uncontested Alpha) on its back side does it count towards devotion (Xenagos, God of Revels)?
I know they have a cmc on their backside, but the question of devotion came up in a game of commander with my werewolf deck last weekend. I don't think it counts, but I'm not certain and I'd be happy to be proven wrong.

While the DFC's converted mana cost is the total of its front sides, its mana cost is still non-existent (so "0"). It has no mana cost, yet has a converted mana cost. The only reason it has a converted mana cost is because the rules give it that. The rules do not grant it anything else from its front side, and in Magic, mana cost and converted mana costs are different things.

Just to make it clear: since the rules give the back face a converted mana cost, but no actual mana symbols, it can't contribute to devotion.