Tidus is the protagonist of Final Fantasy X. He comes from Zanarkand, where he was a riding blitzball player. However, Zanarkand was attacked by a creature called Sin, which caused Tidus to end up in the world of Spira. It was here that he met a summoner named Yuna, who was on a pilgrimage to try and stop Sin.
Although he doesn't reprise his main protagonist role in Final Fantasy X-2, his connection with Yuna is the driving force behind her adventure in the game. He also appears as a playable character in Dissidia: Final Fantasy and its sequel, Dissidia 012: Duodecim Final Fantasy, as well as a cameo appearance in Kingdom Hearts and Kingdom Hearts: Chain of Memories.
