Almighty Shinra

Strongest Shinra is a superboss in Final Fantasy X-2: International + Last Mission. This creature is created as the result of Shinra absorbing the pyreflies of Omega Weapon. When defeated, he can be recruited into the party. The player must release him after his storyline to get the Last Resort Garment Grid.

Strategy
To start out the fight, everyone should be using the Mascot dressphere. On the Garment Grid, the player should have Alchemist one slot over from Mascot so the girls can quickly spherechange. Once the fight starts, Shinra will use his strongest attack right off the bat, Clione. It is necessary to be in Mascot at this point to survive. Afterwards, a girl should use a Megalixir/Last Elixir to gain back the HP lost.

Directly after Clione, Shinra will cast Ultima, which should not deal too much damage with somewhat high Magic Defense. Once he is about to cast Ultima, Rikku should start to change into the Alchemist dressphere. Timed right, she will change after Ultima is cast so that she doesn't get KO'ed by the attack. Once changed, she should immediately mix a Dark Matter and a Potion to cast Miracle Drink on the party, making them invulnerable to all of Shinra's attacks. The party should then use Moogle Beam and Cactling Gun combined with a physical attack from Rikku to deal about 75,000 damage per hit. Fireworks is also a good way

The battle is best attempted at level 99.