Final Fantasy 10: How [SPOILER] Became Sin

The main antagonist of Final Fantasy X is a lot bigger than most enemies in the series, as Sin is a colossal monster that can grind cities into dust with its bulk. The true purpose and identity of Sin is initially a mystery in FFX, but as Tidus continues his pilgrimage across Spira with Yuna and the rest of her guardians, he uncovers a secret plot that has been going on for centuries.

It’s common for bosses in the Final Fantasy series to transform into hideous monsters during the final battle. Garland turns into Chaos, Sephiroth transforms into a hideous, angelic creature, and Neo Exdeath turns into a grotesque fusion of other monsters from Final Fantasy 5. In Sin’s case, the boss is already found in its monstrous form, free to wreak havoc on the countryside. The only time there is any peace in the world of FFX is when a summoner finishes a pilgrimage, calls on the Final Aeon and uses its power to kill Sin – a process that also claims the summoner’s life. This is a temporary solution, however, as Sin will reform a few years later, and the cycle begins anew.

The summoners of the world of Spira travel the land and gain access to a number of different aeons along the way. Once they reach Zanarkand, they learn the truth behind Sin, the Final Aeon, and the cycle of violence that has existed in their world for centuries.

[Warning: SPOILERS for Final Fantasy X below.]

FFX: Braska’s Final Aeon & The True Identity Of Sin

Throughout the entirety of the game, Sin’s true identity is Jecht, Tidus’ father. It’s revealed that each Final Aeon is created from someone deeply connected to the summoner, giving up their life in order to defeat Sin. Once Sin is dead, that person is then revived as the next Sin. This means that, technically, Jecht was turned into Sin by Yuna’s father, Braska, who also gave his life to stop Sin the last time around.

Tidus and Yuna discover Sin’s existence is tied to a being called Yu Yuven, once the ruler of Zanarkand. Yu Yevon uses Sin as a vessel to maintain its immortality. Once the previous Sin dies, Yu Yevon takes over the Final Aeon and reforms it into a new Sin. It’s also Sin’s role to keep technology from progressing too far in order to prevent the invention of conventional weapons that could harm it. In the case of Jecht, he was able to maintain a piece of his consciousness, which allows others to calm his Sin form when the Hymn of the Faith was played. This lets Tidus and Yuna breach Sin’s form, slay Jecht’s Final Aeon form, and kill Yu Yevon once and for all, bringing an end to the story of Final Fantasy X. Sin returns in an FFX sequel novel, but many fans prefer to pretend that doesn’t exist.