Ashura is the arch-fiend that acted as a major villain in Makai Toushi SaGa/Final Fantasy Legend - he was responsible for commanding the four other fiends that antagonised the heroes throughout the story and was seemingly in charge of Paradise.
When the heroes confronted him Ashura was willing to make a deal with them, offering to share the world with them if they'd ally with him - the heroes refused and the arch-fiend fought them but was slain but the heroes are subsequently sent flying out of the tower after the battle via a trap.
However despite his seeming demise in the first game's story Ashura would return as an antagonist in SaGa II/Final Fantasy Legend II, where he was on a quest to obtain mystical Magi in order to try and obtain godhood: Ashura has managed to gain control over his own tower by the time of this story and a new band of heroes seek out his base to put a stop to his plans, taking on the arch-fiend's minions in the process.
Once the heroes reach the arch-fiend himself he taunts them, stating that his minions had already shrunk themselves and entered the body of the healer Ki to steal her magi (which she was somehow born with inside herself) he then states his intent to steal the heroes magi for himself but is ultimately defeated - at the end of the battle he has an ending quote of "No.. No!! ..I ..don't.. wanna.. die.." before he seemingly perishes and giving the heroes a large collection of magi as a result.
However in true Ashura fashion the arch-fiend is back to cause trouble by the time the events of SaGa III/Final Fantasy Legend III come to pass - having somehow evaded death once again he was using a strange disease to transform hapless humans into monsters and once again managed to get himself a stronghold in the form of South Tower.
However the heroes of the story went after Ashura when rumors persistated that he had some Units belonging to the Falcon, a vessel that they used to travel through time, Ashura informed the heroes that the Units were no longer in his possession but fought them regardless alongside two Warrior henchmen.