Game:Ansem, Seeker of Darkness

Xehanort's Heartless is a boss in Kingdom Hearts and Kingdom Hearts: Chain of Memories. He is fought twice in both games under the name "Ansem", a pseudo name he took on from his old master.

1st Battle
In the first battle, Xehanort's Heartless fights Sora, Donald, and Goofy fight in the End of the World, alongside his Guardian Heartless. He takes it easier on the party at first, so fight ferociously but cautiously. Use aerial Keyblade combos, since Xehanort's Heartless floats and attack magic isn't very effective.

At the beginning of the battle, Xehanort's Heartless will make few attacks, which should make attack combos easy to perform. When he does attack, he shoots energy disks resembling Strike Raid, uses his Guardian to attack physically, and sends his Guardian to attach itself to Sora while he creates an energy shield around himself that deals damage. Usually, this can be avoided, as Xehanort's Heartless yells "Submit!" before doing this, so Sora can Superglide out of harm's way. However, in the event when the Guardian does manage to attach itself to Sora, a "?" will appear over Sora's head, and the Attack command will occasionally change to Freeze for the Guardian to hold Sora in place while Xehanort's Heartless does damage to him. It is best to physically attack Xehanort's Heartless while within reach, and heal with Curaga periodically, because the Guardian will gradually reduce Sora's HP. Alternatively, you may stay out of Xehanort's Heartless's reach, and then hit the Freeze command - Sora will just be held in place while Ansem will be too far away to deal any damage to him. Also, this prevents Sora from losing any HP. Be sure to attack Xehanort's Heartless while the Guardian is attached to Sora, as this makes the attachment shorter; it's also a good idea to use special attacks such as Ragnarok and Ars Arcanum to end the attachment and battle sooner.

Once the battle is over, approach to the crater he has created. However, be sure that Sora has plenty of healing items equipped.

2nd Battle
In the second battle against Xehanort's Heartless, Sora fights solo, so remember to heal with Curaga periodically, since Donald won't be around to heal you! Ansem uses two new attacks: one resembles Riku's Dark Aura attack, in which he shoots back and forth across the arena with a shield over his frontside. This can be blocked using Guard or an Aero spell. The second attack is shown by Xehanort's Heartless starting to glow, and he will say the he'll show you his power. This attack has him sending his Guardian into the ground, creating dark pools underneath Sora which, the Guardian shoots out of with its fist raised. Xehanort's Heartless will show the Guardian's return by saying "My strength returns!" During this time, Xehanort's Heartless is invincible, and the attack must be avoided, either by running, Supergliding, or by using Dodge Roll. Failing to evade this attack can be highly damaging, or even fatal, depending on the amount of HP Sora has at the time. Like in the last battle, Xehanort's Heartless has his Guardian attach itself to Sora. However, he will do this much more frequently than in the first battle. As in the first battle, stay out of harm's way by Supergliding. However, if Sora is attached to, do not try to attack while the Freeze option is available. If you do so, Xehanort's Heartless and his Guardian will attack you together for massive damage. Attacking while attached to with the Keyblade will be deflected by a force field as well. To break the force field, use Ragnarok; this is the best way to attack while the Guardian is attached to Sora.

With constant use of Curaga and MP-restorative items, Sora can easily survive this battle. Xehanort's Heartless is especially vulnerable when he calls his Guardian to return to him, so unleash Keyblade combos at this time for massive damage. The third and final fight with Ansem involves the World of Chaos--see World of Chaos for information on the battle.

Kingdom Hearts: Chain of Memories
Riku fights Ansem twice in this game. The first time, Ansem shoots out a bolt of lightning that travels horizontally. This can avoided by jumping or dodging. Ansem's only other attack during this first fight is a weak physical attack using Guardian. The second time Ansem is fought is during the Final Battle of Riku's Story. This time around, Ansem brings into play some of his attacks from the first game, such as the Sleights Dark Rush (where he zooms back and forth across the arena) and Dark Shadow (when he sends his Guardian into the floor, creating pools of darkness that the Guardian rises out of, fist raised). It's best to use zero cards to break Dark Rush (Although it can be jumped over with perfect timing in CoM), but Dark Shadow can be avoided easily by dodging.

In Re:Chain of Memories, note that Ansem still uses his Strike Raid-like attack during the final battle - Riku can either break this attack or dodge it.