Nobody. Xigbar is a Nobody, and hence feels no emotion. Charisma throws against Xigbar have a disadvantage, and Xigbar has a disadvantage on Charisma saving throws.

Fire at Will! Xigbar wields two guns, which, surprise surprise, have ammo. Xigbar has an Ammo Meter that depletes whenever he fires his gun. His ammo always starts at 100 during fight, with a maximum of 150 ammo at a time, and a minimum of 0. If Xigbar doesn't have enough ammo to use an attack, Xigbar cannot use it. Xigbar's only way to restore ammo is to use his "Reload!" bonus action. However, all of Xigbar's attacks (unless specified) can be reflected at him for a 5th of the damage with a well timed Athletics check (changes depending on attack/circumstance).

Boom! Headshot! All of Xigbar's attacks have a chance to "Headshot" on a natural 19 or 20. If Xigbar headshots a target, the target takes double damage from the attack.

Multi-Attack. Xigbar makes 3 Blast Away! attacks.

Blast Away!  Xigbar fires a barrage of shots with Sharpshooter at a target. Xigbar has 3 variations of this move he can use at any time.
Jump Shot: Xigbar fires at a target with 10-50 ft. while doing a flip 20 ft. in a set direction. + 5 to hit, deals 31 (5d8 + 7) piercing damage on hit. consumes 10 ammo.
Teleport Shot: Xigbar gives a few moments notice, then opens a portal up to 10 ft. away from a target within 100 ft. of him and shoots Sharpshooter through. +4 to hit, has an advantage on hit, and deals 23 (4d10) piercing damage. Costs 10 ammo
Running Shot. Xigbar runs up to 20 ft. in a non-set direction while firing Sharpshooter at a target with 40 ft. of himself. + 5 to hit, deals 27 (5d6 + 9) piercing damage. Costs 10 ammo.
Can be used as a counter

Teleport. Xigbar teleports up to 50 ft. away. Simple as that. But if Xigbar wants to combo this, Xigbar can spend 15 ammo to combo Teleport into Multi-attack. Can be used as a counter attack.

New Backdrop! Xigbar changes the surrounding area using his power over space. Xigbar can put holes through the ground, raises the ground up to 15 ft., and completely cut off a chunk of ground from the rest of the surrounding area. Xigbar cannot change the space where a living being is. Xigbar can only use this attack once every three turns. This attack ranged 100 ft. around Xigbar. There needs to be at least 50 ft. of flat space for everything to walk on. If Xigbar is defeated or flees, the area will return to how it was before the battle started.

Warp Sniper. This attack cannot be deflected at Xigbar by normal means. Xigbar fires a giant bouncing bullet that he can redirect using spacial walls he creates. The bullet will bounce a total of 20 times before being destroyed. In between every creature's turn, the bullet will bounce once. The bullet needs to bounce a minimum of 2 times before it attacks a target again. Whenever the bullet goes to attack a target, it has a + 8 to hit, but can be completely avoided with a DC 16 Athletics check. However on hit, it deals 46 (6d12 + 8) psychic damage. However if the DC 16 athletics check succeeds, the target can attempt to follow it up with a DC 19 Acrobatics check to deflect the attack at Xigbar, making him take a third of the damage it would have done. The target can attempt this Acrobatics check 3 times in a row, after which the bullet will continue bouncing controlled by Xigbar. Xigbar can only have one of these active at a time, but once below half health can have up to 3 at one time. Costs 20 ammo. Can be used as a counter.

Arrow Nebula. This attack cannot be deflected at Xigbar. Xigbar fires a purple arrow into the sky. After one turn, the spot where Xigbar shot it will start raining purple arrows. Every 3 actions from that point on, the arrow rain will spread 5 ft. in every direction, to a maximum of covering 50 ft. in every direction. Anyone caught at the edges of this circle will take 56 (8d10 + 11) piercing damage. Note its only the edges of the area that deal damage, and anyone inside the circle is safe from the hailstorm of arrows. However if you are caught in the storm, there's no chance of avoiding or blocking it. Xigbar can only have one Arrow Nebula active at a time. Costs 50 ammo.

Pre-fired. Xigbar fires a few bullets right next to himself. The bullets will float in place for a full turn, not damage and not being interactable. However after one turn passes, the bullets will fire themselves in whatever direction Xigbar pleases. The bullets cover a 15 ft. space and travel up to 70 ft. Anything caught by the bullets while they travel has a disadvantage to dodge on a DC 18 Acrobatics check. If you fail, you take 41 (5d12 + 7) piercing damage, while you take half as much on success. Costs 25 ammo.

Sniping Grounds. Xigbar connects both of his Sharpshooters together to create a Sniper Rifle. Xigbar then teleports to another plane of existance to avoid being caught out by enemy attacks. From this other plane at the end of every turn, Xigbar will choose a random target and fire at them, with the shot having a + 6 to hit and dealing 46 (2d20 + 21) piercing damage. There's only two ways to get Xigbar back into this plane of reality, being A: Finding and going to the plane of reality he's hiding on to drag him out, or B: Successfully reflect his shot 3 times in a row, hitting him and dragging him out. When this attack ends, Xigbar instantly staggers upon his next hit. This attack costs 30 ammo to activate, but doesn't cost any extra to sustain.

The Hattrick. Xigbar's desperation move, only usable while under half health. Xigbar teleports everyone fighting him into a small 25x25 ft. arena, while he floats outside the island, then his turn ends. If Xigbar is attacked while this attack is active, Xigbar simply teleports away from the attack unless he can't see the attack at all. Between every action a creature takes while on the Island, Xigbar will teleport near and shoot a barrage of bullets at a random target, with a + 3 to hit, and dealing 16 (3d8 + 7) piercing damage on hit, then teleports away again. Xigbar repeats this until his next turn, when he'll teleport into the center of the arena and open portals all around the arena. Xigbar will start shooting through all the portals, firing at everything on the island at once. The shots have a + 9 to hit, and on hit deal 67 (4d20 + 14) piercing damage, and also lowers the armor class of anything hit by 7 until the battle ends. This attack also has an increased headshot chance, being a headshot at a natural 16, 17, 18, 19, and 20. After this attack is over, the terrain reverts to what it was before the attack started, Xigbar's ammo is lowered to 0, the rest of Xigbar's turn is skipped, and Xigbar staggers instantly on hit.

Reload! Completely reload all ammo in Xigbar's ammo meter. If used, instantly ends Xigbar's turn if used. On top of this, Xigbar's chance to be staggered after he uses Reload! Is lowered from 7 over to 4 over.

Stagger. If you roll at least 7 over your chance to hit Xigbar, he will stagger, being briefly stunned and allowing the attacker to attack again. If Xigbar is staggered twice, he's launched briefly into the air, making him harder to hit again. If Xigbar is staggered a whopping 4 times, he will break out of the Stagger and unleash one of 3 counter attacks chosen at random, and the attacker's turn instantly ends, no matter how many actions they have remaining. (Look for what attacks can be used as a counter under the attack section.)