Oh well yeah, he can't be knocked out and that kind of stuff. Cut off his arms will hurt, obviously, but it wouldn't permanently disable them. Disperse his mist form too far to reassemble easily, and it'll just take a while for it to reform. His powered form is pretty much invincible, in terms of truly 'disabling' him, but then again, he runs off of magic, and using a form of pure magic will drain what he has quite quickly. When he runs out of energy, he'd simply be sucked back into his giant gemstone and fall harmlessly to the ground. Considering the size and power from it even when drained, it's unlikely anyone would just leave it.