also forms created by pyreflies. Sin, the bringer of destruction, is a powerful fiend that is made of high-density pyreflies; it can control gravitation forces to replenish its strength and even fly. Sin's high concentration of pyreflies affect the pyreflies present in the bodies of those present, it is known as "Sin's toxin". Despite the Final Summoning being able to destroy Sin itself, the central core of Sin, which is an entity known as Yu Yevon, would survive. From this, Sin is "reborn" after a time. Fictional history Spira's fictional history centers around an ancient war a thousand years prior to the start of the game between Bevelle and Zanarkand, the latter's ruler deeming his city's eventual demise and reserve to preserve its memory. Yevon's people became the fayth to create this manifestation and Yevon made himself the core of a powerful monster known as Sin to protect it, though the process destroyed his mind as he continuously maintains Sin's summoning as the creature is compelled to destroy. Through the machinations of Yevon's daughter Yunalesca, Bevelle established a religious faith built on atonement and sacrifice to conceal the spiral of death that runs throughout Spira's history. This process involves Yunalesca teaching a summoner a ritual known as "the Final Summoning", which would give Spira a brief reprieve from Sin's terror in a period known the . However, the Final Summoning is based on a strong bond, and requires a summoner to turn their guardian into the Fayth of a Final Aeon whose summoning kills the summoner who is memorialized as a high summoner. Though the Final Aeon can destroy Sin, it would become a new vessel of Yu Yevon and turned into a new Sin. A thousand years following the establishment of the Yevon Order, Spira became a rustic land, almost completely devoid of large cities and higher civilization. Due to the actions of Sin, and the Yevon ban on machina, few territories reached larger than hamlet size, as they were destroyed by Sin and their populations decimated before they were able to develop. The only cities left larger than small villages were Luca, which houses the only blitzball stadium in Spira, and Bevelle, the center of the temples of Yevon. Yuna and her guardians break the cycle and bring about the "Eternal Calm". As a result of the events in Final Fantasy X, in Final Fantasy X-2 the teachings