The Black Fairy Mavros
Creepysoo showed up with a Life Curse cast on him to see if an undead like him could regain a fresh body. He willingly accepted this experiment as it was a way for him to blend in human society. He even got a skill from it called Living Embodiment which turned him human via a curse. It hampers all of his abilities, but it also protects him from external harm.
Any being that destroys his 'human' body would be cursed by the Life Curse that he learned. He was unable to cancel the effects once he activates it which is why he arrived with Hexy in a human flesh suit. He did not expect that the life curse would infuriate the Black Fairy Mavros, but he was thankful that he got out of it. The only problem is that the anger of the enemy is now directed at him when he is weakened due to the sudden splitting of his two undead knights.