Appearance and Personality
He has not been seen without the skeleton armour on, which gives him the appearance of a man with a long tail covered in bones.
He serves his elder faithfully and has full confidence in him, even when he is about to die. 
Prior to being revealed as Mule, he was only known as the elder envoy. He was followed by his attendants, which were Michael, Apple, Akryung, and a mysterious fourth person. He was later confronted by Baylord Yama and in a bid to save his own life he threatened the people of The Cage using the nucleus of his armour as a bomb. However, the bomb was neutralized by Jordan and Baylord Yama ended up killing him when he lost his leverage.
Powers and Abilities
Skeleton Armor (골격갑주가동): Mule is in possession of a skeleton armour gifted to him by his elder Khel Hellam, which boosts his speed making him really fast.
Skeleton Armor Lethal Move: Green Bone Breath (골격갑주가동살인기 그린본브러l스): A Killer move used by activating the skeleton armour, which produces a blast of green shinsoo. The attack was noted as smelling like crap by Baylord Yama.
Nucleus Bomb: In a pinch, he could use the nucleus of the skeleton armour as an improvised bomb.