Dark Ixion (Final Fantasy X)

Dark Ixion is an optional boss in the international and PAL versions of Final Fantasy X. It can be encountered twice, first time by talking to a Yevon soldier on Thunder Plains, and after that, by pressing X during a thunder strike.

Battle
In the first battle, Dark Ixion counters every attack, and may cause Sleep, Armour Break and Mental Break. His non-elemental Thundaja spell also may be dangerous. As in the other Dark Aeon battles, it's best to use Auto-Life or call an Aeon when the enemy's Overdrive gauge is full, because it can deal disasterous damage. Dark Ixion has low HP, so it can be defeated quickly using the strongest Overdrives several times. The party should have extremely high Agility and Accuracy (about 255). Very high Strength, Defense and Magic Defense are also very useful.

As any other enemy, it can be killed instantly by Yojimbo's Zanmato attack.