Satan

Name: Satan ƒTƒ^ƒ“
Affiliation: Kouma/Fallen Angel
Date of Birth: Unkown presumably before the dawn of man
Martial Talents: General, field commander.
Spiritual Powers: destructive powers, flight, regeneration
Actor: ‰Æ’†�G (Yanaka Hiroshi)
See Also: Shinosuke Yamazaki, Aoi Satan

Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.(Revelation 12:12 KJV)

Satan: I am resurrected; my sin, my darkness. The serpent of old as the eternal undying god. The original insurrectionist who rebelled against the omnipotent father. My name is Satan!
Narrator: Formerly, the highest class head angel, closest to God and revered, the Archangel Lucifer. Because he held such tremendous power, he opposed God the father and was defeated in the following violent battle. God the father banished Lucifer from heaven. He was cast down into the boundless depths of the earth. This was the beginning of hell. And Lucifer became the eternal enemy of God... The birth of the devil King Satan. -- From Kayama's ST1 Translation FAQ.

SPOILER WARNING! Major Spoilers for ST1 and Atsuki Chishio Ni

Satan is the final and form of Aoi Satan and the final boss of the first game. He is litterally the biblical devil, its not totally clear how Yamazaki became Aoi Satan or the host for the true devil. But given Yamazaki's lust for power and his feeling of betrayal for the goverment for refusing to build the Koubu during the first Kouma War, it could be inferred that Yamazaki made a deal with Satan at the end of the Kouma War when he vannished for the power he wanted to defend himself, and then became Aoi Satan. This fits well with the TV series vesion of events, (where ironically he isn't the biblical satan).

Satan has only one real objective to destroy the work of God and condemn humans to suffering, death and damnation. Satan states that he wants to bring judgement to the humans.

After he is defeated Micheal gives him a chance to return to Heaven, Satan seems genuinly taken aback that God would be willing to forgive him and seems touched for a moment. But quickly he snaps back and refuses, saying that he would "live by the sword and die by the sword" and that he would return as long as the wickedness of humans remains in this world.