The Battle of the 1000 Heartless, also known as the Battle of Hollow Bastion, was a major event that took place in Hollow Bastion in Kingdom Hearts II. It featured over one thousand Heartless attacking the Hollow Bastion Restoration Committee and their settlement. Organization XIII purposely began the war to collect more hearts for Kingdom Hearts by using Sora and the power to release hearts through his Keyblade.
Maleficent also participated in the battle in an attempt to seize the world as hers again. The Organization also used Nobodies in the battle to rid Maleficent's weaker Heartless. Another battle featuring one thousand Heartless can be found in the Underworld as match 45 in the Hades Paradox Cup. Like the Hollow Bastion one, it also features Armored Knights and Surveillance Robots.
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. This is because the cutscene was pre-rendered and is probably because of the high amount of objects that were in the area.
In the cutscene, two Arch Behemoths and six Wyverns with their Kingdom Hearts Final Mix color schemes are shown. However, Behemoths and Wyverns never appear in Kingdom Hearts II, except with the help of cheat codes. In Kingdom Hearts II Final Mix, the Behemoths and Wyverns were brought back, but Sora is alone in the middle of the Great Maw. The promotional trailers for Kingdom Hearts II pictured Sora running towards the Heartless, followed by Donald and Goofy.
In one of Nomura's interviews, he reveals that if there is something that needs to be taken away from the game it has to be this battle.
The battle began while Sora and company opened the DTD dataspace in Ansem's computer and were discussing Ansem's identity with the King. When the Bailey was destroyed by the surge of Heartless, the party immediately made their way there, but were forced to linger in the halls of the Castle fighting their way out.
Meanwhile, the Hollow Bastion Restoration Committee made their way towards the Bailey, and then to the Great Maw, to combat the threat. They made themselves ready as thousands upon thousands of Heartless flowed toward the town. Aerith made her first in-battle appearance in the series, aiding Yuffie with her white magic skills, revealing her to be able to cast the Cure spell herself. Cloud and Leon fought side-by-side against a large crowd of Heartless, both making comments regarding their capabilities in fighting off all the Heartless. Later, Cloud has a short reunion with Sephiroth, then runs off after him just as Tifa arrives. Even Stitch, Yuna, Rikku, and Paine help in defeating the Heartless, although they do not have as much of an effect on their numbers.
As Sora and the gang make their way down the Ravine Trail toward the Great Maw, the Committee arrives in various places to help them get down, then disappear to continue the fight.
They do not appear again until after the fight, but it can be assumed that they spent most of the time fighting nearer the town, defending it from advancing Heartless. They appear to be mostly unscathed, and quickly begin working on repairing the town once more.
Sora and company
Although a small minority of Heartless were attacking Ansem the Wise's old castle, Sora and his friends force them back out of the town into the Great Maw. Sora, Donald and Goofy catch up with King Mickey in the Bailey, and defy his orders, going in to help their friends. Upon reaching the Castle Gate, they encounter Demyx, whom 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 have hit Mickey, if Goofy had not pushed him out of the way.
Goofy is hit on the head by the boulder instead and is knocked unconscious. Goofy's subsequent failure to respond to Sora and Donald's attempts to wake him lead the two of them and Mickey to believe he is dead. Enraged, Mickey, Donald, and Sora charge into the battle. Sora is then helped by Yuffie, Leon, Tifa and Cloud to rid the Heartless. However, after the battle through the Ravine Trail, Sora, Donald and Mickey discover that Goofy is alive.
The group then moves into the Great Maw, where they finally behold the leader of Organization XIII, Xemnas. Mickey runs off to confront Xemnas. Before the others can follow, they find themselves surrounded by a great Heartless army. Sora, Donald, and Goofy split up to finish off the numbers quicker, and a great battle ensues, leaving only the three warriors of light standing. The trio eventually catch up with Mickey. Xemnas makes his departure who is chased by Mickey plunging into a Corridor of Darkness. The three have a brief encounter with Axel, who reveals Organization XIII's plan is to have Sora slay Heartless so that they can take the hearts released from the felled enemies. However Axel would not further elaborate on the Organization's plans, but apologized for kidnapping Kairi.
Pitiful Heartless. Mindlessly collecting hearts; not knowing of the true power they hold. The rage of the Keyblade releases those hearts. They gather in darkness, masterless and free, until they weave together to form Kingdom Hearts. And when that time comes, we can finally, fully exist.Saïx explaining the Organization's goal to Sora in Kingdom Hearts II
Following Axel's fleeing from Hollow Bastion with the appearance of Saïx, the trio is further informed of the Organization's plan. However, Maleficent arrives to try doing away with the Organization's meddling, but is quickly beaten by a small group of Dusks Saïx commanded along with the Heartless now allied with the Organization. Before the Organization could collect more hearts from the Keyblade, Maleficent, who had fled into a dark corridor, surprisingly saves the three from a group of Heartless and sends them to their Gummi Ship.
In the aftermath of the battle, Maleficent's power over the Heartless was effectively broken. Organization XIII was able to take control of them in her stead, and began sending them to the worlds which Pete had previously visited.
Although the Hollow Bastion Restoration Committee won the battle, 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 the hearts of others.
Also, in the Corridor of Darkness, where Maleficent sent the party after the battle, the trio obtained several critical clues from Riku that eventually led them to Twilight Town, and then to The World That Never Was.
Sora must defeat exactly one thousand Heartless alone. The battle can be made much easier by using the Reaction Command, however. This allows Sora to perform the Rising Sun Reaction Command, which lets him attack large groups of enemies and devastate them. The Armored Knights are relatively helpless in this way, and to make matters easier, Sora can grab the Surveillance Robots around the area and use them in the Snag and Sparkle Ray Reaction Commands to attack the Armored Knights and other Surveillance Robots.
In the end, although the Armored Knights are not exceptionally strong, their main strength is their great numbers, which compounded with Sora being alone could catch him off-guard. These Heartless are in fact weaker than the normal variety found, possessing less HP and stats. Because of this large number of Armored Knights, the battle could take a long time to complete. But because of the Reaction Commands, this battle is very easy, albeit long.
For the magic lovers, before the battle, equip a good amount of Ethers and keep them in the Shortcuts menu. Also select spells like Thunder and Magnet and put them in the Shortcuts menu. When the actual battle starts up, magic fans can use Thunder multiple times, then use an Ether on Sora. If the MP bar is still pink in color, attack like normal. Another way is to go in Limit Form, then revert back to have a full MP and HP bar. For crowd-control lovers, Magnet is a great spell. The Explosion ability is also highly effective, clearing out a decent radius of foes while not requiring MP.
A possible glitch may occur during battle as the Rising Sun Reaction command causes Armored Knights to become lodged in the mountain scape surrounding Sora, ceasing the ability to use physical attacks. This can be rectified by casting Thunder until all of the enemies are defeated.