Satan

Satan, is the ruler of Gehenna, and the father of two special children. He is the father of the Eight Demon Kings as well.

Appearance.
Satan's true form has not yet been shown. When we possesses someone, he has typical demon features such as pointy ears, long nails, and sharp canine teeth. And also blue flames.

Personality.
When first seen, Satan's mannerisms and laughter bordered on that of insantity and he enjoyed it when his children screamed for help when being sucked into Gehenna gate. This reveals that his cruel and reckless personality does not stop, even before family. Clearly he loved someone. But felt no remorse killing the children.

History.
Satan wandered armound Assiah looking for a host that would not die at his touch, One woman, an Exorcist named Yuri Egin, was immune to Satan's flames. She went looking for him, feeling sorry for him, let him possess her body, so that he could see the world and have normal experiences. It later revealed he inpregnated her during this time. Tome time later, Shiro Fujimoto discovered she was pregnant, then she was accused of witchcraft, and was sentenced to burn to the stake, in a desperate move to save Yuri, Satan possessed so many exorcists, that night became know as "The Blue Night" and he finally had one Exorcist powerful enough to sustain, thus saving Yuri. Yuri fled to a cave, then gave brith.