Finger of God is a weapon that the Citadel automatically fires every so often. It will target anywhere on the map and nuke some creeps. I don't know how much damage it does to Demigods though, as it rarely hits them. It's identified by a bolt of lightning striking an area. It's a nice counter to hordes of creep.

Both light and dark have this same weapon.

I'm pretty sure in its description it says that you do not have to manually fire it.

I dunno

I dunno about your games, but when the opposite team gets it, the HoG seems to have a bone to pick with me. 3 times in a row and popped me while I was trying to escape. It always seems to find it's way to me.

hehehe