Xemnas/Gameplay

Xemnas is the leader of Organization XIII, and is fought as a boss in both Kingdom Hearts Final Mix and Kingdom Hearts II. In Kingdom Hearts Final Mix he challenges Sora at the Hollow Bastion, while in Kingdom Hearts II he fights Sora at both Memory's Contortion and within Kingdom Hearts itself.

Design
During two parts of his battle with Sora and Riku, Xemnas dons armor adorned with dozens of Nobody symbols. His shoulder pad (he only has one, on his left shoulder), helmet, crown, boots, knees, and breastplate all sport these designs. His crown and shoulder pad are gold, while the rest of the armor is colored in light shades of blue and black. He has two white belts on his waist and what seems to be a white tuft of fur on his right shoulder in place of armor. Several cords criss-cross in front of his torso, connecting to massive, oblong pieces of armor worn on each arm.

Xemnas's faceplate is beak-like in structure and he wears clawed, metal gloves. Perhaps the most striking features of this armor are the odd, pulsating growths sprouting from Xemnas's right shoulder and both arms. These growths appear organic and are a mixture of red, orange, yellow, and white. While the larger one on his shoulder seems to connect Xemnas to his dragon-like Nobody battleship, the other two just lie on the ground, seemingly serving no purpose.

In his final section of his battle with Sora and Riku, Xemnas's appearance is unchanged, save for his cloak. His once all black cloak is now a white one covered in black designs, many of which resemble the Nobody logo.

Kingdom Hearts Final Mix
At the start of this battle, immediately Lock-On and summon Tinker Bell. This will minimize the damage Xemnas can do to Sora. He will immediately execute an energy-ball attack, the balls exploding into orb-like, damaging force fields. While it is advised that the player has their most powerful abilities equipped, they must be careful at close range, as Xemnas will counter with a damaging shield technique or a powerful slashing combo. As the player must also be wary of their MP, Elixirs and Megalixirs are strongly recommended.

After about three quarters of Xemnas's pink HP Bar have been depleted, the hooded Nobody will begin to teleport around the battlefield, ultimately increasing his speed. Escape his energy ball or slash/shield attack by keeping track of the dark cloud that surrounds him. Once Xemnas hits his orange HP Bar, however, battle difficulty increases even further. Xemnas will summon a ring of blue Ethereal Blades in the air before him, the blades firing at Sora when Xemnas gives the command. This technique can be avoided through the use of Dodge Roll. When his yellow bar is almost completely depleted, Xemnas shrouds the field in darkness, surrounding himself with energy. Long-range lasers will then fire from him in all directions. Remain close to Xemnas to avoid as much damage as possible. Another option of escape is to use the Glide tactic.

From this point forward, Xemnas's most basic attacks gain more strength, the Nobody now summoning a ring of red blades rather than blue. The effect of this attack is still the same, but damage is increased. Xemnas's final and most dangerous tactic is an HP-draining attack, messing up Sora's commands. Once Sora's HP hits zero, Tinker Bell will revive him. As she can only be used once, the player now must rely even more on his Curaga spell. So long as the player heals periodically and follows strategy options mentioned above, Xemnas will be eventually defeated.

First Battle
When the battle begins, Xemnas will ensnare Sora in a field of energy that will slowly drain his health, then teleport to the top of Memory Skyscraper. Sora must rush to the bottom of the building and use the Reaction Command "Facedown" to charge up after Xemnas. Xemnas will leap down to confront Sora as he nears the top. At this point, one of three Reaction Commands appear depending on how close Sora is to Xemnas. The first is "Clash", where they pass each other harmlessly. The second is "Breakthrough", where Sora attacks Xemnas with a single attack. At the last second, the command changes to "Finish", where Sora attacks Xemnas several times and hits him into the side of the skyscraper. You are recommended to hit the Triangle button at "Finish". Note, however, that not hitting Xemnas will cause him to deal damage to Sora.

After the sequence ends, Xemnas will begin his normal attack pattern. He will teleport in an orb of darkness frequently, emerging to attack Sora rapidly with his Ethereal Blades, spinning and flipping to attack from all sides. These attacks can be blocked with Guard, or more easily, Reflect. Xemnas will also project a barrier, blocking Sora's attacks and knocking him back. He can be stunned, so Sora can easily connect combos. However, Xemnas tends to teleport away right afterwards, or if Sora attacks him too many times, he will teleport away in the middle of the combo.

Later in the fight, Xemnas will repeat the opening sequence involving Sora running up Memory Skyscraper. The Reaction Commands for the second time are the same as the first. As well, when weaker Xemnas teleports more often and quicker than before. Overall, Xemnas is not an overly difficult boss, and can be hit with combos with ease. He can be defeated easily as long as the player heals when needed and has some healing items as back-up.

Replica Data Battle
In his respective data battle in Kingdom Hearts II Final Mix+, Xemnas doesn't start off the battle with the HP drain move. Also, using the "Finish" command on Xemnas while facing him on Memory Skyscraper at the end of the battle leaves him stunned at the bottom of the building with a single HP left, similar to the final battle. Merely repeat tactics used in the fight against the true Xemnas, and he shall fall. This is only the first portion of the battle, Sora then forced to challenge Xemnas's final form with Riku as a Party Member.

Energy Core
The final battle with Xemnas begins. The player must make sure that he or she has saved the game before entering the battle, as this option will not be available again, and there is no turning back. As soon as the battle starts, Xemnas begins to bombard Sora with buildings. Use the Reaction Command to avoid damage, and then pass through the doorway before you into the next area. Run forward and use the "Skyscraper" command to reach Xemnas's massive Dragon Ship. The player must now knock several Time Bomb Nobodies into the power generators of the ship. The player must use "Stunt Dodge" to dodge both the generator's laser attack and explosion upon destruction respectively.

Sora then finds himself in the main core of the ship. Attack the core, dodging aerial attacks from the ship's "claws" and the lesser Nobodies that spawn once the core surrounds itself with a protective barrier. It should be noted that only by destroying the Nobodies does the core become open to attack once again. Use the "Proceed" Reaction Command to enter the next phase of the battle.

Armored Controller
First Incarnation

After destroying the main core of the Dragon Ship, Sora is faced with an armored Xemnas. The Nobody will use a massive sword to deal damage, having a long range. Not only does Xemnas have access to this attack, but those of past defeated Organization members, as well. He can summon Demyx's Water Forms, which can deal great damage, but give much-needed HP Balls upon defeat. Xigbar's Sharpshooters may fire lasers while a ring of fire and Axel's Eternal Flames appear on the ground. Xaldin's lances will cause wind damage, Saïx's Lunatic able to knock Sora back in a powerful shockwave. Xemnas may also select Luxord's Fair Game to damage Sora, too. Merely dodge these relatively weak attacks, and show Xemnas no mercy. Drive Forms can be used for only this portion of the battle, and greatly increase the rate at which Xemnas's HP is depleted. Heal periodically. It should be noted that should the player fall, King Mickey is available to revive Sora, even though he and Kairi were locked outside of the door. Xemnas is also stationary during this battle.

Second Incarnation

After the fall of the massive Dragon Ship at Sora and Riku's hand, it rejuvenates and teleports the two Keyblade wielders to an alternate dimension. The fly to the head of the ship, where they find the stationary, armored Xemnas awaiting them yet again. The Nobody will attack with a long-range sword swipe as in the last battle, dealing a lot of damage on contact. After one bar of HP is depleted, Xemnas will slam his weapon against the floor, sending Sora and Riku flying.

Xemnas will bombard Sora with lasers and buildings, so the player must use the Reaction Commands to get back to the ship. Failure to do so will result in Xemnas blowing Sora away and dealing minor damage. Once this is done, immediately and repetitively use Aerial Dodge (smash the O button) in order to dodge Xemnas's next tactic, one that allows him to summon snow-flake shaped energy that fires lasers with no hope of escape. Should this not be done, the player can attempt Aerial Dodge again, or merely allow damage and then let themselves fall to the point where they can safely glide back to the ship.

After Xemnas's second HP Bar is depleted, these lasers will continue to fire as you grapple with Xemnas. Be aware that he may summon a damaging shield, just as he did in his previous battles. Regardless of his Drive Form levels, Sora has full access to each Form's ability, allowing easier movement and dodging. Riku will also heal Sora with Cure Potion if his HP falls below critical.

Dragon Form
This fight pits Sora and Riku in a Gummi-Ship-style battle against a massive Dragon Ship, which is piloted by Xemnas. Only three commands are available on the menu: Attack, Drain, and Shoot. Use Drain when enemy ships fire lasers at you, filling the Charge Gauge. If you fill this gauge, the Triangle Button can be used to fire a powerful Reaction Command, "Mega-Laser". This attack will, if not completely, drain large portions of the ship's HP without fail. If Time Bombs appear near Sora, he can press the Square Button to fire lasers to deal damage, but the Attack option would offer higher accuracy. Shoot should only be used against enemies that are far out of range. All enemies that bombard the ship via Shoot deal massive damage.

Sora must first tackle the Dragon Ship's tail. Utilizing a combo of the commands mentioned above, this should hardly be a challenge. Xemnas may fire a large array of missiles, however, and since Sora cannot heal in this battle, the player should dodge by flying in circles to each corner of the screen.

After destroying the tail, Sora must defeat the "legs" of the ship. Mega-Laser will come in handy here, and the player can also fly in circles to dodge the snowflake-shaped lasers that are fired. After defeating both of these limbs, Sora can proceed to the wings.

Before the first wing can be destroyed, Xemnas will fire "snowflake lasers" as well as missiles. Both tactics can be dodged via flying to each screen corner. Once this is done, the command process repeats itself yet again. Defeat both wings in order to clear the battle and progress.

Final Battle
Xemnas will first throw Sora and Riku into the air, leading to a series of aerial slash attacks and round-house kicks. It is possible however, to avoid being thrown in the air if the player has Reflega in his magic shortcut menu and uses it immediately after the battle begins. These tactics can be dodged by using the "Reversal" Reaction Command. If the player wishes to deal minor damage to Xemnas as he teleports around, the player can manually select the Trinity Limit ability. This approach would then lead to the "Block" Reaction Command.

Eventually Xemnas will allow Sora and Riku to drop down. He will then teleport around the battle area, shooting threads of dark energy that can be dodged via Reversal. When Xemnas reappears, he uses a clone in an attempt to trick the player. Attacking the wrong Xemnas will result in the true Nobody slashing with his Ethereal Blades or dealing a devastating round-house kick.

As his HP depletes, Xemnas will shoot energy balls that explode to both block and cause damage. When it depletes even further, he begins to teleport rapidly, encircling Sora and Riku with lasers. He and his clone may then appear together or separately to shoot at Sora. These moves can be avoided via Reflega or Guard, and if the player is willing to be wasteful while possibly dealing damage, a Limit. Once these tactics are completed, Xemnas will trap Sora, slowly draining his HP and forcing the player to take on the role of Riku, who only can jump, cast Dark Aura, and attack. While Xemnas drains Sora, his clone will attack Riku with energy balls, slashes, and even the damaging shield tactic. The clone can be annoying, but Dark Aura will stun him just little. Use this time to run to the real Xemnas and Sora, using Dark Aura every three steps until you get to the true Xemnas. Jump to him and execute the Reaction Command in order to free Sora, stunning Xemnas. This leaves the Nobody boss open to great amounts of damage.

Xemnas will then repeat the throwing technique used at the battle's start, repeating his normal attack pattern as well. Just before Xemnas's HP hits zero, he then fills the battlefield with lasers, shrouding the area in darkness. The player must now repeatedly mash and  in order to keep Sora and Riku alive. Failure to do so will spell certain death. Once the area is cleared of lasers, brief cinematics are shown, eventually reducing Xemnas's HP to 1. Simply start a Limit or deal a combo finisher to finish off Xemnas.

It should be noted that Riku will heal Sora when his HP is low. Items still should be brought into battle, as it is best to be hit by Xemnas's drain attack with a full bar of HP. Ethers are also good for restoring much-needed MP. It should also be noted that while Xemnas's final attack brings him to 1 HP, the player can deplete his HP to 1 before the attack is executed, as well. Riku cannot die in this battle, because he is needed for the entire battle. The only time that Riku can die is when Xemnas starts to drain Sora's HP.

Data Rematch
The battle with Xemnas's Data Replica is the same as the original, save for a few differences, the obvious one being that he has more health. Another change is after Xemnas tosses Sora and Riku in the air and attacks them long enough, a cinematic plays where Xemnas knocks Sora's Keyblade away. At this time, the player should activate the Reaction Command Defend, where Riku tosses Sora's Keyblade back to him and they both force Xemnas away (doesn't deal damage by the way). After that the battle plays out the same, the only other difference is that Xemnas can use his "Invitation To Nothingness" attack twice, so healing often is a MUST! To that end, have a lot of Elixirs and Potions. Also, have the Cure spell in your shortcuts. Just follow these tips, and the ones above and Xemnas should fall with ease.

Trivia

 * Strangely enough, immediately before the first battle with Xemnas in his armor, we see Kairi and King Mickey locked outside Kingdom Hearts, but that same battle is one of the only battles where King Mickey can save Sora if he is defeated

Gallery
A Time Bomb and two other Gummi Ship Nobodies appearing during the final showdown with Xemnas, and the Glider used by Riku and Sora during Xemnas dragon battle