Ainz Ooal Gown

Arcane Warding. Ainz begins combat with 150 temporary hit points. If reduced to 0, he can use a bonus action to regenerate 75 on his turn (3/Day).

Aura of Dread. Creatures within 60 ft. of Ainz who see him must make a DC 24 Wisdom Saving throw or be frightened for 1 minute. They may repeat the save at the end of each turn.

Legendary Resistance (5/Day).  If Ainz fails a saving throw, he can choose to succeed instead.

Legendary Archmage. Ainz can concentrate on two spells at once, though not two of the same spell. He also ignores verbal, somatic, and material components for spells of 7th level or lower

Master of Death. Undead under Ainz's control do not count against his maximum for control undead or animate dead. He can control up to 500 CR worth of undead at once.

Ring of Infinite Magic. Allows the use of wish once per long rest without penalties.

Robe of the Undying Lord. Grants immunity to critical hits and the frightened condition.

Spellcasting. Ainz is a 30th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 27(30), +19(22) to hit with spell attacks). He knows all necromancy, conjuration, and evocation spells and the following:

At Will: mage hand, prestidigitation, detect magic, shield, counterspell
3/day each: finger of death, disintegrate, teleport, time stop, power word kill, forcecage, simulacrum
1/day each: wish, meteor swarm, true resurrection, imprisonment, foresight, reality break

Overlord’s Requiem (Recharge 5–6). Ainz unleashes a storm of necrotic energy in a 120-ft-radius centered on himself. Every creature of his choice must make a DC 27 Constitution saving throw, taking 120 (20d12) necrotic damage on a failed save, or half as much on a success. Creatures reduced to 0 HP are disintegrated, leaving only magical items.

Staff of Ainz Ooal Gown (Artifact). Grants +3 to spell attacks and DCs, has 10 charges. Expend charges to cast disintegrate, finger of death, or power word kill without using a spell slot. Regains 1d6+4 charges daily

Summon Dark Knights. Ainz Ooal gown conjures his loyal undead generals to the battlefield. As an action, Ainz summons up to 3 Death Knights (CR 17 each) or one Dark Champion (CR 20 variant) in unoccupied spaces within 60 feet of him. These undead are fully loyal to Ainz and act immediately after his turn. They remain until destroyed or until Ainz dismisses them (no concentration required).

• If used within his lair or demi-plane, Ainz can summon 5 Death Knights or One Dark Champion and 2 Death Knights instead.
• The summoned undead vanish after 1 hour or when Ainz is reduced to 0 HP. 

While at least one summoned Death Knight remains, Ainz can't be surrounded—his minions always take up positions to protect him, granting him half cover against attacks and spells from one direction of his choice.

Ainz can take 5 legendary actions, choosing from the options below. Only one legendary action can be used at a time, and only at the end of another creature's turn. Ainz regains spent legendary actions at the start of its turn.

At-Will. Ainz casts an at will spell.

Command Dark Knight (Costs 2 Actions). A summoned Death Knight immediately makes a melee attack or casts a spell it knows.

Fallen Down (Costs 3 Actions). Ainz calls forth his ultimate-tier magic, unleashing pure destructive force upon his enemies. All creatures in a 60-ft radius sphere centered on a point Ainz can see within 120 feet must make a DC 27 Dexterity saving throw, taking 180 (40d8) radiant and force damage on a failed save, or half as much on a success. Constructs and celestials have disadvantage on the saving throw. Ignores resistance to force and radiant damage and bypasses immunity to force damage. This counts as a 9th-level spell effect for counterspell/dispel purposes, but it is not technically a spell.

Maximize Magic (Costs 2 Actions). The next spell Ainz casts before the end of his next turn is automatically treated as if he had cast it with the maximum possible damage roll—no dice are rolled. This ability does not affect spells with only saving throw effects or non-damaging spells.

Paralyzing Glare. One creature Ainz can see within 60 feet must make a DC 24 Wisdom saving throw or be paralyzed until the end of its next turn.

Quickened Spell (Costs 3 Actions). Ainz casts a 5th-level or lower spell without consuming a spell slot.

Teleport (Costs 2 Actions). Ainz teleports to an unoccupied space he can see within 60 feet.

Twin Maximize Magic (Costs 5). The next spell Ainz casts this round is both Maximized and Twin Cast. Twin Cast allows Ainz to cast the spell again at the same target or a different one.