Originally Posted by
Tavrobel
At first, cast Slow on Evrae if you have it. continue your normal cycle of attacks until it either Slows Evrae, or Evrae casts Haste on itself. After then Slow spells are made void.
If you can survive until Haste, then make sure you are Hasted when Evrae uses it. Stock up on Al Bhed Potions, and try to have the Alchemy ability attached to an Armor (IIrc think Alchemy is an Armor ability). Take advantage of Cid's Missiles when possible, and keep either Rikku and Tidus available to give commands.
If you used Slow, then good for you, since Lulu is near useless for the rest of the battle.
From here, you have two choices, doing a far-off assault, or a full-on frontal take-on, involving all melee characters. Far-off takes longer, but is generally safer until Evrae catches up (this is an attack), and Missiles can only be used from here. You should by now, know how many haloes you have of missiles. Wakka, Lulu (LOL), Kimahri, and Rikku are good here.
If you want to take him on, have Auron, Tidus, Wakka, or Kimahri do the damage through normal attacks. Unleash overdrives when possible. If Kimahri knows "Use," then have him slop out the Al Bhed Potions. Otherwise, attack normally, and heal properly by backing away or bringing in Rikku.
Can't really do anything besides that. If you are over-leveled, you shouldn't have any problem now. If you are under-leveled, you still shouldn't have any problems by now.