The Battle of the 1000 Heartless (or Battle of Hollow Bastion) was a major event that took place in Hollow Bastion. It featured 1000+ Heartless attacking the Restoration Committee and their settlement. Organization XIII purposely began the war to collect more hearts for Kingdom Hearts. Maleficent also participated in the battle in an attempt to seize the world as her's again.
Although a small majority of Heartless were attacking Ansem the Wise's old castle, Sora and his friends forced them back out of the town into the Great Maw. Sora, Donald and Goofy caught up with King Mickey in the Bailey, and defy his orders, going in to help their friends. Upon reaching the castle gates, they encounter Demyx, who they previously met in the Underworld at Olympus Coliseum. After a tough battle, Demyx falls and fades back to darkness. Mickey catches up with Sora, Donald and Goofy, accepting to help them. However, a Surveillance Robot's laser hits a boulder which would've hit the king, if Goofy wouldn't have pushed him away. Goofy, being hit on the head instead, is seemingly dying. Enraged, Mickey, Donald, and Sora charge into the battle. However, after a battle through the passageways through the land, Sora, Donald and Mickey discover that Goofy is alive.
The group move into the Great Maw, where they finally beheld the leader of Organization XIII, Xemnas. Mickey runs off to confront Xemnas. Before the others can follow, they find themselves surrounded by 1000 Heartless. A great battle follows which leaves only Sora, Donald and Goofy standing. The trio eventually catch up with Mickey. Xemnas makes his departure, chased by Mickey into a corridor of darkness. The three briefly have encounters with Axel, Saïx and Maleficent, the plot of the Organization revealed to them. Maleficent surprisingly saves the three from a group of Heartless and sends them away from the world, ending the war.
- Sora (commander)
- King Mickey (commander)
- Leon (commander)
- Xemnas (commander)
- 1000+ Nobodies
- 1000+ Heartless (allied with Organization XIII later in the war)
- 1000+ Heartless
- Many Nobodies
- The Hostile Program
- Goofy (Knocked unconcious, thought dead)
In the aftermath of the battle, Maleficent's power over the Heartless was effectively broken. Organization XIII was able to take control of them, and began sending them to the worlds which Pete had previously visited.
Sora began to doubt his purpose, knowing that Organization XIII would take the hearts of any Heartless he would defeat. However, Goofy reminded him that to do nothing would allow the Heartless to continue taking over worlds.
- In the cutscene prior to the battle, Sora, Donald and Goofy wield their basic weapons (Kingdom Key, Mage's Staff and Knight's Shield, respectively). However, when the fight starts they carry their equipped weapon.
- In the cutscene, black behemoth heartless are shown, but behemoths never appear in Kingdom Hearts II.