Kingdom Hearts coded
Form 1—Neo Darkside
Sora's Heartless fights very similarly to Darkside, except that every move unleashes a Debug Attack. The left fist uses Blizzard, and the right fist uses Fire. The head launches Slow, avoid it at all costs, if possible. Focus on dodging attacks and then attack the fists when they are on the ground. Make sure not to fall off the platform while dodging. Be sure to heal when necessary.
Form 2—True Form
Sora's Heartless is invincible under his shield. Notice that a white, ghostly Keyblade is hovering over the field. This is what Sora has to hit. To find it, hold still a moment until it comes lunging at Sora. The target Keyblade is different from the ones Sora's Heartless attacks with, but looks similar. When successfully attacked, Sora's Heartless will turn into a simple Shadow. Use a simple combo on the Shadow, and the second phase shall be cleared.
In the third phase, several copies of Sora's Heartless appear in the place of a single enemy. Dodge their attacks and wait for white, ghostly Keyblades to appear again. Hit the copies of Sora's Heartless while their shields are down to make them disappear. If the chance is missed, hit their Keyblades until they are open again. Repeat the pattern against the last remaining copy of Sora.
In this phase, Sora will be facing off against four copies of Sora's Heartless, all with shields up. Whenever a copy is defeated, it will turn into a ghostly Keyblade and keep attacking, eventually turning back into its original form. Focus all attacks on the real copy of Sora's Heartless. Only bother with the fakes if they get in the way. Sora's Heartless will eventually turn into a Shadow again.
Sora's Heartless retains its weak Shadow form that was previously battled in the second phase. This battle serves as nothing more than an ending battle, and does not pose any challenge. Simply attack the Shadow a few times to complete the final phase of the battle with Sora's Heartless.
Kingdom Hearts Re:coded
Form 1—Neo Darkside
First, bring many long-ranged commands, as it is difficult to attack it at the close range. After the Rail-Shooting, Sora's Heartless has transformed into its Darkside form. It can use its right arm to smash the ground, creating a fire-based shock wave which deal a great amount of damage and three fire balls which will slowly chase after Sora. Another attack is using its left arm to smash the ground, which will produce an ice-based shock wave that can freeze Sora. After that, it will create three ice pillars around its hand which sprout up after a short time, making it harder to hit its hand. These two attacks can be avoided by jumping at the precise time its hand hits the arena and attacking its hand later. Another attack is when Sora's Heartless shoots a column of light into the sky, which summons many light columns around Sora, that can inflict Slow on if it hits.
After its HP dwindles, it will disappear in light and upthrust Sora directly under the ground. Quickly dodge roll the circle of light that appears under Sora. If the punch misses, it's hand will be immobile for a while, quickly attack it. After several punches, Sora's Heartless will prepare the explosion, Sora can attack it and deal more damage but the explosion will deal a great amount of damage to him. To avoid this attack, quickly run to a corner and Sora will receive no damage from the explosion. Afterward, it will begin its attacks again.
Form 2—True Form
After beating Sora's Heartless in its Neo Darkside form, it will transform into an AntiSora-like form. It will attack by using its ghost copies of the Keyblade to attack, these types of attacks can be blocked easily. Another attack includes Sora's Heartless floating into the air and summoning many copies of ghost Keyblade to fall behind Sora, dodge the Keyblades by using Dodge Roll. After the attack ends, a golden Keyblade will drop to the ground signified by the burst of light and create a yellow radial aura. Quickly run into it, then use the Reaction Command Drag n' Drop which if used against the boss, will transform the boss into its original form, a Shadow Heartless which is much easier to fight.
Form 3 and 4—Offshoots
These forms are similar to the True Form, except the boss can summon two clones to attack. The clones take extra damage, but while they're present the main AntiSora enemy cannot be damaged. Note that the clone's Keyblade rain will not have the golden Keyblade. In form 4, the Keyblade rain of the main AntiSora will last longer, and the golden Keyblade will always drop in the center of the arena, striking Sora with a shockwave if he is on the ground. A special ability called Drag 'n' Drop can be used only in this fight.
Notes and references