As has usually been the case in these Grey Warden-specific quest, you'll be able to take one side or the other. G: What happens at location G is going to depend entirely upon the decisions you make. So, methodically kill the Forgotten Spirits, utilize the anvils as soon as they appear, and before long, your enemy will fall. This is the only way to do damage to the central foe. By examining the anvils when they appear, you will send a powerful burst of energy towards the stone faces, damaging them. Dealing with these enemies quickly is the key to winning this fight, since when you kill a certain number, small anvils will appear in one of four locations around the stone faces. The stone enemy will spew out Forgotten Spirits like it's going out of style.

You may be confused as to how to deal with this enemy, but there is a key to this battle that will make it far, far easier, and plenty-expedited, too.

The boss here is some sort of strange stone-headed device that constantly turns, spawning enemies. F: At location F, the first of two bosses here can be found.

Dragon age origins anvil