Darkness-Protocol grants an entire unit Ambush, which is quite the piece for a good unit. Nightmare-Protocol gives Fear - You're not that powerful in melee, but maybe it'll work for a unit that is.
If you're not looking to shoot much, then you can exchange the staff for a free hyper sword for AP 1 and Rending.
If the model could already cast, then it's getting a +2 to block.