Cloud was my first, simply because I went in order of easiest difficulty story to hardest difficulty. Once I got to the Onion Knight though, I just loved his playing style, and used him whenever I had a choice of who to play as. He quickly made it to level 100 without any grinding on my part.

Quote Originally Posted by Skyblade
If only there was something that effective for AP. Even level 1 Chaos is annoyingly long to master everything with.
Beckoning Cat accessory + Diamond equipment bonus + maximum AP Bonus day + AP Bonus + Chaos Battle = 54 AP per fight. A battle against a normal character under the same circumstances will still yield you 18 AP per battle.