Quote Originally Posted by Endless Twilight
I don't remember it being said that Yunalesca is his daughter.
I don't quite exactly remember either, but I think Yunalesca was (Yu) Yevon's daughter. She created the final summoning to both punish Bevelle and to honor her father, and instilled Yevonism among all Spirans. Not 100% sure about that though. When Yevon became Yu-Yevon by absorbing the pyreflies of those who sacrificed themselves (later the fayth), he created the armor known as Sin, and Yunalesca created a method to "destroy" Sin.