Tidus is an optional boss in Final Fantasy X-2: International + Last Mission and Final Fantasy X-2 HD Remaster. He is fought in the Fiend Arena in the final tournament, the Farplane Cup. Tidus will join the player's party after being defeated. In the HD Remaster version, if he is released without the default name of ????, he cannot join the Gullwings again.
Tidus has high Agility and can cast Hastega on himself making him even faster. He uses normal physical attacks, but most commonly resorts to using Spiral Cut and Blitz Ace, two of which are Swordplay Overdrives he can use in Final Fantasy X. Spiral Cut hits one character for moderate physical damage, while Blitz Ace hits a character nine times for major damage. He can inflict strong Delay on a character with Delay Buster, heal himself with a Mega-Potion for 2,000 HP, and even turn temporarily Invincible with a Hero Drink.
When defeated, he drops two X-Potions or a Sword Lore. Once Tidus has been defeated in the Fiend Arena and the player reaches the end of the Farplane Cup, they will be given the option to recruit Tidus. He can learn his Overdrives Spiral Cut and Blitz Ace from Final Fantasy X as abilities.
Tidus is powerful if the player is not at a high enough level, or if they do not have sufficient defense. Level 99 and Champion Belt will take care of part of it, while Rikku's Mascot ability Power Eraser will help lower his attack power. If Power Eraser is used three times it will bring Tidus's attack power down to -x10, the max. This can also be achieved with other abilities like Full Break/Quartet Knife (either from Paine's Cutlery moveset or a recruited Mega Tonberry or King VERMIN!); while this will also lower Tidus's Defense, Magic, and Magic Defense, it takes longer.
The player should make Rikku cast Dispel or Crackdown once Tidus casts Hastega on himself. The player should make Yuna and Paine attack with Moogle Beam and Cactling Gun to deal the most damage possible. The player should use Moogle Regenja on the party to get a slight upper hand. If Tidus uses Hero Drink, the player must focus on keeping the party alive until his Invincible status wears off.
If the player uses captured fiends, they must again be at a high level and have high overall stats. Should they have Break Damage Limit and maxed Strength, they can defeat Tidus with approximately three uses of Fireworks.