Satan (悪魔, Akuma?) is the main antagonist of Final Fantasy II Muma no Meikyū, a novelization of Final Fantasy II that diverts a lot from the game. He is the true mastermind behind Emperor Mateus's actions and his unearthly powers. Satan is never mentioned within any versions of Final Fantasy II or any official guidebooks.
Satan is the Lord of Hell who corrupts Emperor Mateus and allows him to summon hellish creatures into the mortal realm.
In the past, Satan's main power came through influencing others, with the conduit of influence being that of a person's natural level of malice. Palamecia proved to be an easy target for him to spread his influence into the kingdom, and if a ruler were to be immune to Satan's influence, he would find a way to eliminate them. Such a fate befalls that of the Emperor's father, wanting to open the Palamecian borders for diplomatic relations with other kingdoms. Satan was unable to dissuade the monarch, and so gives him a heart-attack, killing him instantly. As soon as Mateus is crowned Emperor, Satan has him as a pawn in his game, knowing that Aile, the Emperor's mother may be onto his plot. Satan removes Mateus' memories of her, as influencing him to outright kill her wasn't an option.
When the Emperor is defeated by Firion and his friends, they find the Stone of Iludia containing Satan's soul. When stone is destroyed, Satan attempts to possess Leon's body, but he is intercepted by the Wyvern King's Mist, which sends Satan's soul back to hell.
Satan comes from a Hebrew ha-Satan which means "the accuser." It is the name of the Devil in Abrahamic religions. Satan is also one of the seven princes of Hell in Christian Demonology. He is attributed the deadly sin of Wrath.
demon is "an evil spirit or devil, especially one thought to possess a person or act as a tormentor in hell".A
The word comes from the ancient Greek daimon (translated into Latin as daemon), meaning a spirit/god. On its own, the word is neutral, neither good or evil. The English translation later became synonymous with devil, to the point the words are commonly interchangeable now.