Mass level your legendary Pokemon. Mesprit, Regigigas, Cresselia, Heatran, Palkia, and Dialga are the ones I used. Once they're up to around 75, try it out. First, send out Cresselia IF your Cresselia has a fairy type move. Volo will send out a Spiritomb. Now, Volo will often send out Pokemon that has a type advantage to your Pokemon. He has the same party as Cynthia: Arcanine, Lucario, Spiritomb, Togekiss, Roserade, and Garchomp, up until the point of which he uses Giratina in both forms. You should be able to use one regular super effective move to deal with the main party through swapping out Pokemon. Use Regigigas and Heatran as tanks when you're starting to run low on Pokemon to use. When running low on Pokemon on the Giratina phases, use agile style moves whenever you can get another action immediately after. Use the second one to revive something. I'd revive Cresselia or Mesprit if you can, because usually their agile style moves open up new availabilities. I'd use Extrasensory for Mesprit, Moonblast or Psychic for Cresselia. After the first, revive the other. After the second, revive Dialga if it's down. If not, revive whatever or attack again if there's nothing to revive. Once Cresselia/Mesprit is down, swap to Dialga. Have Dialga use an agile style move like Earth Power, only as long as it opens up another action. For that one's revive, if needed, revive Palkia. If not, just attack again. Once Dialga is down, swap to Palkia. You should be on second Giratina phases by this point, but you still do the same maneuver. Palkia would use a strong style move with high or always accuracy if phase two Giratina is below half health, or an agile style and revive maneuver if it's above. I'd revive Heatran to restore Palkia and use Earth Power because it's not as slow as Regigigas. If the agile style move brings it down to half or below half health, then once Palkia is back up, have Palkia use an agile style high or always accuracy move, as long as it opens up another action. Then with that second action, use a strong style high or always accuracy move, specifically Dragon Pulse. And there you have it. How I beat Volo.
