Magus , aka Janus Zeal, of Chrono Trigger fame.
A villain who never really turns good, players nevertheless ay have him join the party and help save the world. He had a certain style and attitude that made him super-cool, and he’s one of the more power-house team members. I always would have liked to have learned more about his upbringing among the Mystics, his rise to power, and the source of the rivalry with Sir Cyrus & Frog/Glenn.
Lastly, it always bothered me how CT ends with this great set-up for a game featuring him on a quest to find his sister Schala (sister, not half-sister, the guy who did the original US translation has said in interviews that was a mix-up). Instead, when Square finally gave us a sequel, it was Chrono Cross, a “sequel” whose developers deliberately tried to disassociate from it’s predecessor as much as possible to prevent accusations of being a mediocre re-hash (acording to the director in an interview). And yes, I know Guile was originally supposed to be him, and I know the whole Magil from Radical Dreamers thing; but it ain’t him in CC.