Aezi'el, the Fallen One
Large Celestial (Fallen One), Neutral Evil
Armor Class: 51 (natural armor, shield)
Hit Points: 11080 (267d10 + 9612)
Speed: 120 ft, fly 520 ft
STR 80(+35) DEX 68(+29) CON 80(+35) INT 77(+33) WIS 53(+21) CHA 80(+35)
Saving Throws: Str +76, Dex +70, Con +76, Wis +62, Cha +76
Skills: Acrobatics +70, Athletics +76, Deception +76, Intimidation +76, Religion +74, Stealth +70, Survival +62
Damage Resistances: acid, bludgeoning, cold, force, lightning, piercing, psychic, slashing, thunder
Damage Immunities: fire, necrotic, poison, radiant
Condition Immunities: charmed, exhaustion, frightened, paralyzed, poisoned, stunned
Senses: Blindsight 20 ft, Darkvision 1500 ft, Tremorsense 50 ft, Truesight 300 ft, passive Perception 31
Languages: Celestial, Common, Infernal, Telepathy
Proficiency: +41
Challenge: 160 (??? XP)

TRAITS
Legendary Resistance (18/Day). If Aezi'el fails a saving throw, they can choose to succeed instead.
Lord of Fate (10/Day). Aezi'el can force a creature to reroll an attack or saving throw. They then are allowed to choose which roll the creature uses.
Master of Magic. Aezi'el may use their bonus action to cast a spell from their spell list before using their action as normal.
Action Surge (17/Short or Long Rest). Aezi'el can push themself beyond their normal limits for a moment. On their turn, they can take one additional action. They can use it only once on the same turn.
Indomitable (65/Day). Aezi'el can reroll a saving throw that they fail. If they do so, they must use the new roll.

ACTIONS
Multiattack. Aezi'el makes thirteen attacks with their Infernal Whip and one Shield Bash, or thirteen attacks with their Celestial Trident.
Celestial Trident. Melee or Ranged Weapon Attack: +165 to hit, reach 10 ft or range 100/340 ft, one target. Hit: 57 (5d8 + 35) piercing damage, or 62 (5d10 + 35) piercing damage if used with two hands to make a melee attack. Any creature hit by this attack must succeed on a DC 48 Constitution saving throw or become paralyzed and stunned. A creature with a Chaotic or Lawful alignment takes 96 (9d20) radiant or necrotic damage, with a Chaotic aligned creature taking radiant damage and a Lawful aligned creature taking necrotic damage.
Infernal Whip. Melee Weapon Attack: +165 to hit, reach 55 ft, one target. Hit: 51 (3d10 + 35) slashing damage. If Aezi'el chooses, any creature hit by this attack automatically becomes restrained (escape DC 48), and takes 86 (13d12) fire damage and 86 (13d12) necrotic damage at the start of its turn. Aezi'el may move a restrained creature up to 50 feet in any direction, but cannot attack another creature with their Infernal Whip until the restrained creature escapes.
Shield Bash. Melee Weapon Attack: +165 to hit, reach 10 ft, one target. Hit: 38 (1d6 + 35) bludgeoning damage. If the target is a Gargantuan or smaller creature, it must succeed on a DC 48 Strength saving throw or be pushed 30 feet backwards and knocked prone.
Lance of Demonic Divinity (Recharge 6–6). Aezi'el creates a 15-foot long spear of pure demonic and divine power, and hurls it at a creature within 500 feet of them. The creature must succeed on DC 48 Dexterity saving throw, taking 325 (50d12) radiant or necrotic damage (Aezi'el's choice) on a failed save or half as much damage on a successful one.
Flame Breath (Recharge 4–6). Aezi'el exhales a plume of pure black flame in a 300-foot cone. Any creatures caught in this area must succeed on a DC 48 Dexterity saving throw, taking 264 (48d10) fire damage on a failed save or half as much damage on a successful one.
Shield Wall. Aezi'el protects themself from all incoming damage, reducing it by half (rounded down) until the beginning of their next turn. While in this stance, they can also make one Shield Bash attack. Aezi'el must be wielding a shield to use this action.
Spellcasting. Aezi'el casts one of the following spells, using Charisma as the spellcasting ability (spell save DC 84, +76 to hit with spell attacks):
7/day each: wish

BONUS ACTIONS
Instant Teleportation. Aezi'el immediately teleports up to 1200 to a point they can see. If a creature occupies that point, they are immediately pushed 20 feet away from that spot.
Gaze of Terror. Aezi'el gazes at a creature within 30 feet of them, their eyes burning with arcane malevolence. The creature must succeed on a DC 48 Wisdom saving throw, or become frightened of Aezi'el for 10 minutes. That creature also has disadvantage on their next attack. While frightened, they may make another saving throw at the end of each of their turns, ending the condition on a success.

REACTIONS
Second Wind (24/Short or Long Rest). Aezi'el has a limited well of stamina that they can draw on to protect themself from harm. They regain 272 (1d10 + 267) hit points.
Intercept. When a creature adjacent to Aezi'el makes an attack that requires a roll to hit, Aezi'el can intercept the attack with their Infernal Whip. Aezi'el makes an attack roll with their Infernal Whip. If the roll is higher than the attack roll of the creature, the attack of the creature misses.

LEGENDARY ACTIONS
Extra Attack. Aezi'el makes one attack with one of their weapons.
Reposition. Aezi'el moves 60 feet without provoking Opportunity Attacks.
Destructive Orb (Costs 2 Actions). Aezi'el creates an orb of crackling, warbling energy, hurling it at a point they choose. On contact with a surface, the orb explodes, sending destructive power coursing through a 50-foot-radius sphere. A creature hit by this attack must succeed on a DC 48 Constitution saving throw, taking 112 (32d6) force damage and gaining three levels of exhaustion on a failed save, and taking half as much damage and only gaining one level of exhaustion on a successful one.