The attack begins as planned, and eventually the monster opens up its mouth to suck in the airship. Inside Sin they find Seymour and battle him a final time. Despite yet another powerful form, Seymour Omnis, he is defeated. With nowhere for him to run, Yuna sends the rogue Maester. Before disappearing, Seymour says he is glad it was Yuna who would send him, but even if they defeated Sin, Spira’s sorrow would continue. At Sin’s Core in a place similar to the blitzball stadium from Dream Zanarkand, Tidus is reunited with his father who only has a short time left before his mind fully becomes Sin’s. Jecht turns into Braska’s Final Aeon, Sin’s true form but the party kills Jecht and saves him from the nightmare of being Sin. Jecht says goodbye to Tidus and scolds him for crying, but the battle is not won yet.
Yu Yevon, requiring an aeon to inhabit, takes over Yuna’s aeons one by one. The party destroy each one as Yu Yevon possesses them, and with nowhere left to hide, Yu Yevon himself appears, revealed to be little more than a floating bug-like creature. The party destroys Yu Yevon, and defeats Sin. Auron, his mission complete, requests that Yuna send him. With the fayth retiring from their thousand-year dream, Tidus bids farewell as he fades from existence. Though Yuna tries to stop him from leaving, she falls right through him. Yuna proclaims her love for him (in the original Japanese version, she thanks him instead) and Tidus embraces her. He jumps off the edge of the airship, falling through the clouds, where he sees Braska, Auron, and Jecht waiting for him on the Farplane and high-fives Jecht, symbolizing that he has reconciled with his father.
Now a High Summoner, Yuna gives a speech at the Luca blitzball stadium about Spira’s future: Sin is finally dead, and Spira is theirs again after 1,000 years of terror. The Eternal Calm has begun, and Yuna resolves to aid in the world’s reconstruction, and concludes with, “The people and friends that we have lost, and the dreams that have faded, never forget them“.
In the depths of the ocean, Tidus wakes up and swims toward the surface with a smile on his face.