When Darkaun finished healing his eyes, Zaos had damaged his legs so much that Darkaun could see a pool of blood around him. He tried to protect his body with the dark aura, but somehow, Zaos managed to surpass even that. While that was annoying, it was also exciting for a battle-hungry demon like him.
"That is very good," Darkaun said. "No wonder I can't see any fear or doubt inside you. Someone with your skills probably has what it takes to challenge our master."