Ongr the unbound is tameable with the ascian collar. By himself he is very formidable - but he is upgradable to a group. In my current game he has 420 attack and 384 hitpoints after upgrading to a group of four. Not intended?
The only downside to taming him is that he never gains experience from combat. He might gain xp from quests but haven't finished any with him in the army yet.
