Xemnas, The Superior of the In-Between

Nobody. Xemnas is a nobody, and hence feels no emotion. Charisma saving throws/checks have a disadvantage against Xemnas, and Xemnas has a disadvantage with Charisma saving throws/checks.

The Void King. Xemnas has three forms he takes throughout battle. Xemnas always starts a fight in basic form. Basic form Xemnas has 218 HP, 14 AC, and all of Xemnas' other stats. After Basic Form Xemnas is depleted to 0 HP, Xemnas changes to Armored Form. In this form, Xemnas is completely immobile, but has access to way more attacks, has 305 HP, and 21 AC. Lastly if Armored Xemnas is defeated, Xemnas will transform into Final Xemnas, his last form. Final Xemnas can move once again, has 349 HP, and 18 AC. Only if Xemnas is defeated in his final form will Xemnas die, being taken to the void, for eternity.

Ethereal Lances. Xemnas makes a 5 hit combo with his Interdiction against a target he can see within 30 ft. of himself. If Xemnas is too far away at the start of the combo, Xemnas will simply glide over to the target while swinging. Every 10 ft. the target is away from Xemnas, Xemnas wastes one swing. Each swing has a +6 to hit, and deals 37 (4d12 + 7) slashing damage on hit. Only usable while Xemnas is in Basic Form.

Ethereal Wall. Xemnas summons a transparent wall that cannot be seen normally. This Ethereal Wall can only be seen with a passive perception of 25 or higher, or by rolling a DC 27 Perception check or higher. Xemnas can move through this wall freely, but any other creature that attempts to move through it will be bounced backwards 15 ft., while taking 52 (4d20) psychic damage. Once the wall is either walked into by something other than Xemnas, attacked by something other than Xemnas, or has existed for 5 turns, the wall will fade away. Xemnas can have 4 ethereal walls up at once. This attack can be used as a counter in Basic Form, but can be used normally in all forms.

Gateway of Darkness. Xemnas uses the realm of darkness to instantly warp up to 70 ft. away from his original spot. If Xemnas succeeds a DC 17 Arcana check while doing so, Xemnas can combo this attack into Ethereal Lances in one action. Only usable in Basic Form. Xemnas can use this attack as a counter in Basic Form.

Breakthrough. Xemnas locks a target within 75 ft. of himself using Chains of Nothing. The chains will slowly eat away at the targets health, dealing 9 damage every turn until removed. The only way to remove the chains is to challenge Xemnas to a "Breakthrough" where you must roll Acrobatics, Athletics, and Arcana against him. If you win no rolls, Xemnas will instantly incapacitate your character, or instantly kill them if they're below 30 hp. If you win one roll against Xemnas, nothing happens. If you win two rolls against Xemnas, you get to land one free attack against him. And if you win all three rolls against Xemnas, you instantly delete half of his total HP. This attack can be used for a very stylish finish against Basic Xemnas. However your campaign shouldn't know this is only his first form. Xemnas can only use this in his first form.

Remembrance of the Nothings. Xemnas uses one of the 12 weapons of the other Organization XIII members. This attack changes depending on the weapon.
Oathkeeper and Oblivion. 10 tile range, 21 (3d10) necrotic damage and 21 (3d10) radiant damage. + 4 to hit.
Foudre. 15-30 tile range. + 2 to hit. Deals 27 (4d8 + 7) lightning damage.
Graceful Dahlia. 5 tile range. + 7 to hit. Deals 34 (6d8 + 8) Necrotic damage.
Fair Game. 5-15 tile range. Xemnas challenges a target to roll a d20, then rolls a d20 himself. If the target rolls higher, the rest of Xemnas' turn is skipped. If Xemnas wins, the target takes double damage from Xemnas' next attack, and if they tie, nothing happens.
Arpeggio. Xemnas summons water clones of himself that have 20 hp, 9 AC, and can attack by shooting lasers from 5-30 ft. range. These lasers have a + 4 to hit, and deal 31 (5d8 + 7) radiant damage on hit.
Lunatic. 5 tile range. Spreads a 10 ft. shockwave. + 6 to hit. Deals 38) 6d10 + 5) bludgeoning damage on direct hit, while the shockwave does half as much.
Eternal Flames. 5-20 ft. range. + 5 to hit. Deals 27 (3d10 + 9) fire damage twice.
Book of Retribution. 40 ft. range. All targets in range must pass a DC 19 Arcana check, or be blinded for the next 3 turns, and take 21 (5d6 + 5) psychic damage.
Skysplitter. 5 tile range. + 1 to hit. Deals 73 (8d12 + 19) bludgeoning damage.
Frozen Pride. Gives Xemnas a shield that has 30 HP, and 15 AC. The shield must be destroyed to damage Xemnas. Xemnas can only have 1 shield at a time.
Lindworm. 15-40 ft. range. + 4 to hit. 24 (6d8) piercing damage.
Sharpshooter. 40-60 ft. range. + 7 to hit. 42 (5d10 + 11) piercing damage.
All of these attacks can only be used by Armored Xemnas.

The Chains of the Void. Xemnas launches a barrage of Gray and White chains from his arm. These chains will extend up to 120 ft., then disappear into nothing. Anything in the path of the chains can attempt a DC 18 acrobatics check to avoid them, and in fact ride them right behind Xemnas. If you are hit by a chain, you'll take 32 (5d12) Necrotic damage, and Xemnas can force you to move to any spot within the chain's range. If you hit a solid wall, Ethereal Walls included, Xemnas can teleport behind you and use this attack again. Xemnas can only use this attack in Final form. Can be used as a counter.

Blast of Banishment. Xemnas launches two electric spheres at a target he can see with 140 ft. of himself. One sphere will fly straight at the target, with a + 7 to hit and dealing 67 (8d12 + 15) lightning damage on hit. The second orb will hover in the air, and will only attack the target when Xemnas commands it to. Xemnas can command the second orb to fly at the target whenever he wants, including outside of his turn, unless he is staggered. The second orb has the same stats as the first. Xemnas can have up to 3 extra orbs floating at a time. Xemnas can only use this attack in Final Form.

Remnants of Nobody. Xemnas dashes around, and a clone of himself appears. Xemnas' actions per turn is reduced to 2 for the next turn, but both him and the clone have 2 actions. The clone will be allowed to attack next turn, and then disappears again after it attacks. The clone can't be damaged, but can damage others. While the clone is out, Xemnas and his clone cannot use "We Shall Go Together" or "No More Eternal than that Radiance of Yours". Every other attack available to Final Xemnas is available. Can only be used in Final Form.

The Energy of Despair. Xemnas uses his lasers in a variety of different ways. He can use them to:
Launch a rapid fire of Lasers at one target. This attack has a + 5 to hit, and deals 11 (4d4) Radiant damage up to 10 seperate times.
Teleport behind a target and circle them in still lasers, then fire them once the target is surrounded. +4 to hit and has an advantage to hit. Deals 46 (6d10 + 7) Radiant damage on hit.
Throw out a laser orb, and activate it on demand. The orb will fire at the closest target to it when activated. Xemnas can activate the orb at any time, including another creature's turn, unless he is staggered. The lasers fired from the orb have a + 3 to hit, and deal 26 (6d6 + 7) radiant damage on hit.

We Shall Go Together. Xemnas teleports in front of a target within 75 ft. of himself and throws them into the air. Once in the air, Xemnas will attempt to combo the ever loving snot out of his target. Xemnas gets a total of 9 actions to try and attack only the target he threw into the air, with the caveat that the target has an advantage of dodging Xemnas' attacks, and Xemnas can't use "No More Eternal than that Radiance of Yours". If the target manages to survive Xemnas' entire onslaught, the rest of Xemnas' turn is skipped, and Xemnas is guranteed to get hit by and stagger to the next attack that hits him.

"No More Eternal Than That Radiance Of Yours". Xemnas' desperation attack. When Xemnas' HP hits zero, before Xemnas dies Xemnas will use this attack as one last ditch effort he is killed. Xemnas traps everyone he is fighting in a black void. Xemnas can use any of his attacks aside from "We Shall Go Together", with the key difference that all of his attacks have a disadvantage to hit, but deal 1.5x more damage. Xemnas gets a full 15 turns to attack any and all targets in the void, with his opponents getting a turn every 3 actions, but being unable to hurt Xemnas further. After Xemnas expires all 15 actions, for his last ditch effort to kill everything, Xemnas will trap all of his targets in a giant dome of Ethereal Lances. The lances will start barraging at everything in the dome. Xemnas will then start challenging the creatures in the dome to skill checks of his choosing, but the party is allowed to choose who rolls against him. Note that Xemnas rolls as well, without advantage, and the party's goal is to roll higher than him. If Xemnas is defeated in the dice roll 13 times, the attack ends with no target taking any damage. If the targets fail to outroll Xemnas a collective of 7 times, then Xemnas wins, and instantly kills everything in the dome. If the targets survive this last attack, every single member of the party is allowed to get one last completely free hit on the fully stunned Xemnas, before he completely explodes into nothingness. If your party manages to get through this. Congratulations, they've managed to defeat the final gauntlet of Organization XII, and have completely defeated the Organization.

Stagger. If Xemnas is his by 8 points over his AC, Xemnas will "Stagger", giving his attacker another attack against him with full chance to hit. If Xemnas staggers twice in a row, Xemnas is launched into the air, giving his attacker a disadvantage to hit him. If Xemnas staggers 4 times in a row, Xemnas will break the stagger with a counter attack, having an advantage to hit the person who staggered him, while also immediately ending their turn. Look under "actions" for what attack Xemnas can use as a counter attack. Note that Armored Xemnas cannot be staggered.

Eternal Nothingness. While Xemnas is in his Final Form, he has an advantage against dodging all forms of enemy attacks, while also having an advantage to land all attacks, and an advantage on all forms of skill checks, Charisma included.

King Nothing 5/Day. If Final Xemnas fails a skill check, he can instead choose to succeed at it. This ability does not apply to the final hits of "No More Eternal Than That Radiance Of Yours."