Final Fantasy X
Voice Actor: N/A
Yu Yevon is the main villain in Final Fantasy X, as he is the one who ultimately created Sin and carries on the process of its existence. While he created it with relatively good intentions, gradually the energy he exerted to summon Sin took its toll over his mind and his humanity faded into nothing.
When Zanarkand was on the brink of defeat by Bevelle's forces, Yu Yevon helped to create Dream Zanarkand, so that Zanarkand would never sleep. To protect this, he also created Sin, which had the order of destroying all Machina and any settlement which gained in size.
Starting The Cycle
Shortly before creating Sin, Yu Yevon informed his daughter Lady Yunalesca of his plans and he entrusted her with passing on certain knowledge to the citizens of Spira. This ultimately created the teachings of Yevon and Yunalesca presided over the Final Aeon.
Every time the Final Summoning defeated Sin, Yu Yevon would then use it to reproduce a new Sin and this process continued without any problems for around 1,000 years.
Fighting For His Beliefs
After defeating his daughter Yunalesca, Tidus and his party manage to pierce Sin and confront Yu Yevon himself. Nobody had ever done this previously, and Yu Yevon was forced to fight them using the only tactic he knew; Possessing Aeons.
When Yuna's Aeons were all used up, Yu Yevon had nowhere else to go Yu Yevon was defeated, ending 1,000 years of punishment at the hands of Sin.