Satan is a minor antagonist in Final Fantasy: The 4 Heroes of Light.
Before the events of the game, Satan arrived in the Kingdom of Horne and managed to transform King Horne into a parrot. After, Satan assumed Horne's form and ruled the kingdom, while the real king went into hiding in Kuore's house. On the day of Aire's birth, Satan went into the Magic Laboratory and attempted to make a deal with Louhi. After the deal was finished, Louhi gave Satan the magic Desolator in exchange for Aire.
Fifteen years later, Satan called Jusqua to the castle and ordered him to go to the Northern Caves. Before Jusqua left, Satan gave him a Fire Tome, even though magic is illegal in Horne. Later that day, Brandt is also called by Satan to go save Aire from Louhi and Brandt accepts his mission. When Brandt and the others defeat Louhi, all the citizens of Horne are turned into stone, but Satan manages to flee before the curse hits him.
After being sent fifteen years into the past, the party goes to Horne and follows Satan and the chancellor into the catacombs. There they find Satan attempting to make a deal with Louhi to obtain the ultimate magic in exchange for Aire. The party desperate to find answers heads to Louhi's manor. After defeating Louhi again, the party finds out that King Horne was turned into a parrot by Satan and the demon is assuming his form. King Horne then ended up at Kuore's house.
The party returns to the Magic Laboratory and meets with Satan, Brandt and the others use the Lamp of Truth on him and reveal his true form. The party manages to defeat Satan and return King Horne into his true form. Later Satan is revived within the Star Chamber, but he his defeated once more.
Satan is fought twice in the game, once in the Magic Laboratory and another time in the Star Chamber.
Non-Final Fantasy guest appearances
In Bravely Second: End Layer, Satan appears as an optional boss fought west of Yunohana as part of the Seven Sins sidequest and represents the sin of Wrath. It gives access the Yōkai to the Diabolism spells Wrath and Three Blades.
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.
The other major demons in the game also allude to one of the seven princes of Hell in demonology.