DFFOO Ultimecia Heretics [Operation: Airborne Interception] (Xande, Balthier, Penelo) 1001K Score 

Xande
Balthier
Penelo
Diabolos
Ultimecia Friend
1002K Score
78 Turns
In simple turns, its a DPS race that requires you to kill the mobs as fast as possible. Xande takes care of that alongside some good AoE Damage from Balthier too. The boss’s unique gimmick is that whenever it lands, it will cleanse its debuffs and summons the mobs. It will also periodically Oil Charge to get a whole bunch of BRV.
At 79% and 49%, the boss will remove the first 3 buffs the party has and replace them with its own unique debuffs, which you will also need to cleanse either with Balthier or Penelo.