Young Xehanort is an optional boss in the international and Final Mix versions of Kingdom Hearts Birth by Sleep. His boss battle is unlocked when the protagonist returns to the Land of Departure after defeating Vanitas Remnant, on a save file in which it is still accessible. Despite this odd situation, his scene is within canon, and is considered to occur at the save file's point in the story. Defeating Xehanort will grant a unique Keyblade named "No Name", but he can be fought again by leaving Land of Departure and then returning.
Kingdom Hearts Birth by Sleep
Young Xehanort has a variety of powerful attacks, all of which can defeat the protagonist instantly if they are unprepared. However, nearly all of these attacks can be blocked or dodged with practice.
Kingdom Hearts 3D: Dream Drop Distance
Xehanort employs two different phases in this fight, both which make use of his time manipulation abilities and fast strikes. If unprepared, each of his attacks are capable of inflicting serious damage and cumbersome status effects.
Once his health is reduced to 1, he will stop time and teleport to the center of the area, summoning a large clock. Riku has about a one-second window to trigger a Reality Shift to break the spell and continue onto Phase 2. If the latter is not triggered, Xehanort resets time - and the battle - back to the start of Phase 1 with 1/3 of his max health.
Riku must defeat Xehanort within the clock at the center of the area, which is continually counting down. The time allotted is dependent on both game difficulty and damage dealt. If the clock isn't destroyed before the time is up, Xehanort resets time - and the battle - back to the start of Phase 1 with 1/3 of his max health.
Kingdom Hearts Birth by Sleep
Young Xehanort is a powerful boss and one of the strongest enemies in the game. His attacks are varied and hard to predict, similar to those of the Lingering Will. Not only is he immune to all status effects, but he has a great deal of HP as well. The boss is very swift and can inflict massive damage to the protagonist, quickly knocking them out unless they have Second Chance or Once More equipped. Xehanort is also adept in defense; he can use Renewal Barrier if attacked too much, and he sometimes rewinds time after taking damage, allowing him to recover some of his lost HP.
As Xehanort's HP dwindles, he goes even further on the offensive. He will often start one of his long-duration techniques, then continue to attack with different techniques while the first one is playing out. Xehanort will also clone himself, creating four copies that can attack and move independently of the true Xehanort. However, the clones can dissipate after being hit once, so try to use a multi-hitting attack to clear the clones. His most frustrating tactic is to snare the protagonist with his Collision Magnet, then immediately following it up with another attack and a game over (although there are very rare occasions in which the protagonist can escape before Xehanort strings together another attack). Collision Magnet can be avoided easily by simply dashing towards Xehanort when he jumps in the air, and also seems to be canceled if Xehanort pulls the protagonist up against a wall.
After half of his heath is gone, Young Xehanort will begin to turn invisible. While he cannot be locked on, he does leave a faint shimmer and can be "visible" through his Ethereal Blades, so he can still take damage. He still uses his old abilities, but since he is invisible, it is harder to see when he uses them. However, he also gains new abilities, such as firing a beam that inflicts Doom and forces mashing to escape, and casting Mega Flare and Meteor to inflict massive damage.
Xehanort will attack whenever an opening to do so presents itself, but it is easy to heal safely by simply dashing far away from him first with either Slide, Dodge Roll, or Cartwheel. It is also somewhat easy to guard against his attacks by mashing , so the protagonist can also heal by using Renewal Block or Renewal Barrier and deliver damage through counterattacks. Because Xehanort leaves little time for the protagonist to act, it is unwise to use any advanced or ultimate commands, as they take too long to fire and reload. Shotlocks are also good options, but Xehanort tends to evade the Shotlock reticle, and can use Renewal Block to heal himself if the Shotlock hits him too much. If the protagonist decides to rely on Shotlocks, they should stock many Elixirs in order to make sure their Focus Gauge never runs out. D-Links can also work, especially Goofy's for Ventus and Aqua due to the Goofy Spin finisher allowing free movement and rapid blows. However, Xehanort may turn invisible in response, so it may not be ideal to use them. Finally, since Xehanort leaves little time for Keyblade combos, the protagonist's equipped Keyblade and Finish command are not important, but the Keyblade equipped should lean towards the Strength stat.
The safest and simplest way to defeat Young Xehanort is to simply use a deck of 2-4 Cure-type commands, and fill the rest with Fire/Thunder Surges. Thunder Surge is generally better because it grants access to the Thunderbolt Command Style, and Thunderbolt's finisher, being an area-of-effect attack, is more effective at striking Young Xehanort than Firestorm's. A good way to arrange the Command Deck is to have Thunder Surge, Cure, Thunder Surge, Cure and so on, so that both commands are easily accessible and it also helps with not needing to cycle through commands that are reloading. With this deck, the protagonist can basically use Thunder Surge over and over, even when Xehanort is invisible, damaging Xehanort if they hit him and often knocking him out of his combos. The protagonist should make sure to use Thunder Surge so that they go through Xehanort and winds up a short distance past him, rather than next to him, but should dash away instead if Xehanort is right next to the protagonist, as Thunder Surge has a tiny but noticeable start-up lag. Thunder Surge can even be used as a pseudo-dash in order to avoid Xehanort's techniques, like his Collision Magnet. If the protagonist is ever hit by an attack, they should immediately start dashing away, normally, and heal with Cure as soon as they are clear from Xehanort. If playing as Ventus, it's a good idea to stock up on Double Crunch Ice Cream to activate Wingblade, which allows him to hit Xehanort with a combo of Keyblade attacks that he can't easily break out of. Even after setting up a working deck and overall strategy, victory against Xehanort relies primarily on luck, due to his penchant for using unavoidable, instant-death combos.
In the Final Mix versions, the difficulty of the boss fight is slightly toned down. The protagonist can now escape after being ensnared by the Collision Magnet attack by Air Sliding before the second attack, therefore avoiding the lethal combos that were inescapable in the original version. In addition, Thunder Surge is even more useful, as it can easily lead into the powerful Rhythm Mixer Command Style.
Kingdom Hearts 3D: Dream Drop Distance
To provide for defense, Riku should equip Dark Barrier, Dark Roll, Counter Aura, Leaf Bracer, Second Chance, Once More, and Slow Block. His Command Deck should include homing attacks like Balloonga, Firaga Burst and Dark Firaga, as well as powerful attacks like Dark Aura, Dark Splicer, Meteor Crash and Shadowbreaker, and healing commands like Curaga. Also, make sure to have two Spirits that have healing commands, like a Meow Wow, a Komory Bat or ones that can cast Support Magic like Haste, Spirit Roar at the same time as well.
Young Xehanort is an aggressive fighter and it can be difficult to score hits on him as he can trap Riku in a flurry of combo attacks that rapidly drain his health. Dark Barrier followed by Counter Aura is an effective way of damaging him, although keep in mind that some of his attacks are not easy to block and should be evaded using Dark Roll or Shadow Slide. In Critical Mode, Xehanort can run to Riku (or not) and perform a more violent and fast combo followed by an aerial combo, which can rapidly put Riku to 1 HP and Game Over if not blocked or evaded in time. If Riku gets caught in these combos, the player shouldn't move the joystick until it ends in order for Second Chance and Once More to save him, as moving in the air cancels the enemy's combo and Xehanort purposely delays his combos to avoid these abilities, but not long enough for Riku to recover.
Xehanort tends to warp away from projectiles and attack commands, but will be open to attack when he pauses to launch his own ranged attacks. Xehanort will periodically teleport away and fire dark projectiles at Riku. Defend using Dark Barrier, staying near to or far away from him, or dodge continually. If the projectiles connect, they will inflict Slow, so quickly cure it with Esuna (Riku's spirits can have this command) or a Panacea if Slow Block is not equipped. He can also summon giant ice blocks that must be blocked or dodged. When Xehanort prepares this attack, move close to him, blocking the ice blocks, and use Counter Aura in front of him. Make sure to watch how he warps around the arena, because it will signal which attack he will use, and will provide Riku enough time to use powerful attacks such as Dark Aura. If timed carefully, Dark Aura will keep hitting Xehanort and stops his movements for a while, dealing heavy damage.
Alternatively, continue using Firaga Burst, Baloonga, and other attack magic in conjunction with spirit attacks. Keep also in mind the Haste Support Magic after being cast on Riku can be handy, not only to speed up the reloading times but also his main combos, which can stagger Young Xehanort as well. After Xehanort takes enough hits, he will transform his Keyblade into a shield and if Riku hits it, Xehanort will counterattack. If he teleports up and falls, he will whip Riku multiple times. Get ready to block or to Shadow Slide when he reaches the ground. If Xehanort teleports constantly from right to left, he will prepare to charge at Riku. He will teleport like this twice; once he warps the fourth time, get ready to block or use Shadow Slide. If he is a fair distance away, he will start teleporting from side to side again, gradually getting closer to Riku. Get as close to Xehanort as possible when this occurs. After he teleports the third time in this manner, use Dark Barrier near him to block the lasers and use Counter Aura in front of him. If possible, utilize Shadow Slide and Shadow Strike to attack and stop Xehanort's attack.
Once Xehanort's health has been depleted to 1, he will freeze time and warp into a giant Clock that appears in the center of the arena. Wait until the option to perform a Mirage Split Reality Shift appears. This will trigger the final stage of the battle. Note that the symbol for activating the Reality Shift will appear for less than one second. If Riku misses the timing, Xehanort will rewind time to the beginning of the fight and regain some of his health (approximately two and a half life bars). His health must be depleted again in order to perform Mirage Split, but this time, the symbol for activating Reality Shift will remain for a longer period of time.
For the final stage of the fight, Xehanort remains inside the Clock, which is now vulnerable to attack. Though he does not attack Riku directly, he creates half-invincible clones of himself to defend the Clock. The clones will attempt to swarm Riku with ethereal blade combos, X-slashes, and fiery tornadoes, but may occasionally disappear if attacked. It is safer to evade these attacks than to block them, as blocking those attacks will lock-out the clock. While the Clock is open to attack while the clones are not on the field, as this phase is more time based than the previous one, Riku should have Spirit Roar and Haste cast on him by his spirits so that he can inflict more damage while not being restricted to waiting for his commands to reload, for the reason that if the hands on the Clock strike 12 before Riku destroys it, it will rewind time to the start of this phase and regain his lost health of the previous phase. As Xehanort will stop his attacks before it rewinds time, Riku should finish him as fast as possible when it stops attacking if the Clock is close to be defeated; however, after Xehanort rewinds time once, the total health of the Clock will decrease to the same amount as Xehanort's first phase's, and thus, for the next times this phase will restart, making it easier to destroy the Clock on the next try. Multi-hit warping attacks such as Dark Splicer and Dark Aura can bypass Xehanort's clones and remove multiple health bars off the clock, even finishing it off if at low health. Do this with caution, however, as Riku can be attacked and deflected by incoming clones, especially those which use combos and fiery tornadoes, which can knock him away when using Dark Aura.
Due to the relentless assault of the clones, leaving few to no windows of opportunity to attack, a reliable strategy is to activate commands like Firaga Burst while in midair. Releasing the commands at the apex of Riku's Doubleflight will allow Riku to avoid interruption from most of the clones' attacks, with the exception of the X-slashes.
If Riku is supposedly not strong enough to destroy the clock in time, he can, while dodging the attacks, restrain from attacking and wait until the Clock rewinds time, where next time it will have less health, to have a chance to finish it in time.
Notes and references