Cloue took a version of Bahamut on too. But those two are the only ones to defeat Bahamut single-handedly. Also, the Warrior of Light is definitely the main character of Dissidia, as Chaos is fought in FF1 as the final boss.
I liked FF4 more tbh. Those Atma weapons, and the Sasquatch with the rage ring, and all of those relics pulled me in. I've always loved the musical score in the older FF series, which was another reason why I could spend untold hours playing them.
I like Final Fantasy I, it's actually one of my favorites just after VI and V. If anything, it gets a lot more praise than II or III that are just forgotten.
Also if you haven't played Dragon Quest III, you should try it, it pretty much sh_ts on FFI and their release was not so far appart.