Via Infinito, Floor 40. Kill Dark Elemental. Tip: Get Paine or Yuna Dark Knight with Charon mastered. Be sure to have 9999 HP and just kill yourself to kill this bastard fast. Otherwise, in like the 2nd turn, you'll die because he'll cast Ultima.

The Via Infinito is located in Beville. Once you arrive at Beville, go to the main building. Then go right. The Kinderguardians will be there. Then, take the portal and you're there. Don't bother with Charm Bangle, cause it won't work.

Cat Nip: When in SOS (yellow HP), does 9999 damage every hit. Equip Speed Bangle and Gunner, use Trigger Happy (both level mastered) and enjoy that 30k+ damage you pull out on anyone.