Boss from Final Fantasy VI, a member of the Warring Triad alongside Sophia (Final Fantasy) and Zurvan (Final Fantasy). His name is given as Sephirot in concept art, but in the game he only appears as "Majin" (localised as Doom in the SNES and PS1 versions, and Demon in the GBA version).
He would later appear in Final Fantasy XIV under his original name.
He's not to be confused with Sephiroth from Final Fantasy VII, who was also designed by Tetsuya Nomura.