'Satan,' is the god of the demon world and father of Rin and Yukio. Satan is very powerful even to the extent of whoever he posseses starts to rot.

Father Fujimoto being possesed by 'Satan'

One of the few people Satan hasn't been able to posess is Father Fujimoto, the strongest exorcist of True Cross. But Rin mortally wounded his soul by telling him to stop pretending to be his father, and that caused him to let Satan take full possesion. Satan is also the true father of Rin Okumura and Yukio Okumura. But only Rin inherited his abilities. Satan also says that any body he touches will start to decay such as Rin's Mother and Fujimoto.


Satan physically doesn't have a form in reality, but if one gets possessed by him, the person will take on Satan's physical traits like pointy ears, sharp demonic claws, sharp teeth, spiritual wings, a flaming tail, the body will start to rot, and they will bleed through the eyes, nose, and mouth.


Satan is the only demon who can make the mid-high demon, The Gehenna Gate. Satan also said himself that he created the Koma Sword to supress Rin's power to stop him from taking his demonic nature form. Due to his excessively high power rate, not even the strongest of exorcists can last 5 to 10 minutes of possesion.