I'm not aware of anything. It's odd because Yu Yevon is probably the biggest protagonist in an FF game ever. He has basically changed the whole of Spira around him. There are also major contradictions all of which lead back to him. On the one hand, he is religion, on the other he is death and justice. But in his purest form he is just a self-righteous murderer. Yet he never speaks, he never justifies himself. He is just there, at the end, as one of the most pointless 'bosses' in history. It's very odd that Jecht is seized upon as a major protagonist when he has been dragged in and bound to his fate without desiring it. Yevon only pops up towards the end of the game, though I guess a part of it is about illustrating the corrupt nature of his religion.