The Final Aeon (究極召喚, Kyūkyoku Shōkan?) is the aeon that a summoner gains at the end of their pilgrimage to Zanarkand. The Final Aeon is created from someone who shares a deep relationship with the summoner: a friend, family member, or lover. Lady Yunalesca was the first to call the Final Aeon, which was her husband, Lord Zaon. The aeon is seemingly intended to be used only once, during the final battle with Sin, in a ritual that is called the Final Summoning.
The aeon has enough power to be able to pierce Sin's armor, but when Sin is defeated, Yu Yevon emerges from his armored shell and takes control of the Final Aeon and dies as a result. It unknown whether or not the possessed Final Aeon is what kills the summoner or not. Yu Yevon begins using the aeon to rebuild Sin, and this period of rebirth is known as the Calm.
During the game, the Final Aeon is mentioned frequently as the goal that Yuna is hoping to achieve; however, because of the path the storyline takes, she does not receive her Final Aeon, as she learns of the futility of trying to defeat Sin with the Final Summoning. In the final battle before challenging Yu Yevon, the party meets and fights Braska's Final Aeon, who is Jecht, the last fayth that Yu Yevon used to create Sin.
Known Final Aeons and their FaythEdit
Final Aeon is Jecht's EX Mode. As Final Aeon he gains the Regen status, which slowly regenerates HP. Jecht also gains the ability "Full Combo", letting him continue his Bravery combos even if the initial strike misses. This lets him overwhelm opponents with powerful combo attacks, and also makes it easier to strike when pausing to charge up his attacks.
Final Aeon reappears as Jecht's EX Mode in Dissidia 012.