The 100 Summoner Battle

The 100 Summoner Battle is Roxas and Riku vs hundreds of Summoners, and all The Nightmares they summon. In order to beat this army of baddies, you'll need Dark Riku and Shadow Roxas, since they can cancel Summoners' summons. Afterwards, your rewarded with a fight to the death with Abyss Twirler, the commader of the Summoner Horde.