About Final Aeon
The Final Aeon (究極召喚獣, Kyūkyoku Shōkanjū?, lit. Ultimate Summoned Monster) is the aeon a summoner gains at the end of their pilgrimage to Zanarkand. The aeon is intended to be used only once: during the final battle with Sin, in a ritual called the Final Summoning (究極召喚, Kyūkyoku Shōkan?, lit. Ultimate Summoning).