And what good would a servant like that be, huh? They would need to cripple the Domineering Emperor permanently, to let him live. I doubt a peerless master of such a sect would be willing to live the rest of his days like that. He would kill himself. The dude is asking for the impossible in his emotional distress, plain and simple. It's also extremely rude to ask Woo Moon of all people for such a favour.