Azalin Rex (Paladin)

Darklord Resilience (Recharges after a Short or Long Rest). If Azalin would be reduced to 0 hit points, his current hit point total instead resets to 500 hit points, he recharges his Touch of Dread, and he regains any expended uses of Legendary Resistance. Additionally, Azalin can now use the options in the “Mythic Actions” section for 1 hour. Award a party an additional 85,000 XP (170,000 XP total) for defeating Azalin after his Platinum Brilliance activates.

Special Equipment. Azalin Rex wields an Unholy Avenger. (Holy avenger with necrotic damage).

Legendary Resistance (3/Day). If Azalin fails a saving throw, he can choose to succeed instead.

Rejuvination. If Azalin's body is destroyed, but not his phylactery, he gains a new body in 1d10 days, regaining all its hit points and becoming active again. The new body appears within 5 feet of the phylactery.

Command Undead. Azalin and all undead within 60 feet of him cannot be affected by turn undead.

Whirling Dirvish. Once initiative is rolled, Azalin begins to dance around the battlefield in a whirl of colors and robes, flanking does not provide advantage against him.

Magic Resistance. Azalin has advantage on saving throws against spells and other magical effects.

Unholy Smite.  Azalin can 

Spellcasting. Azalin is a 19th level spellcaster. Its spellcasting ability is Charisma (spell save DC 26, +16 to hit with spell attacks.). Azalin has following Paladin spells prepared:
1st level (4 slots): command, compelled duel, searing smite
2nd level (3 slots): hold person, magic weapon
3rd level (3 slots): dispel magic, elemental weapon
4th level (3 slots): banishment, staggering smite
5th level (2 slots): destructive wave (necrotic)

Multiattack. Azalin attacks 3 times with his Holy Avenger. He can substitue one attack with Touch of Dread. 

Holy Avenger. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 17 (2d6 + 8) [slashing] damage and 11 (2d10) necrotic damage. 

Touch of Dread. (Recharge 5-6). Azalin touches one creature within 10 feet of him. The target must succeed on a DC 26 Constitution saving throw or take 44 8d10 necrotic damage and be poisoned for 1 minute. While poisoned in this way, the target is also blinded and deafened. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Parry. Azalin adds 6 to its AC against one melee attack that would hit it. To do so, Azalin must see the attacker and be wielding a melee weapon.

Azalin can take 3 legendary actions, choosing from the options below. He can take only one legendary action at a time and only at the end of another creature’s turn. Azalin regains spent legendary actions at the start of his turn.

Dirvish Dance. Azalin moves up to his speed without provoking opportunity attacks.

Darklord’s Flare. Azalin flares with the horros of the domains of dread and each creature within 5 feet of him must make a DC 23 Dexterity saving throw. On a failed save, the target takes 26 (4d12) [slashing] damage 

Summon Underlings (Costs 2 Actions). Azalin Summons (1d6) Greater Zombies.

If Azalin's Darklord trait has activated in the last hour, he can use the options below as legendary actions.

Fear the Night (Costs 2 Actions). Azalin summons (1d4-1) Nightwalkers around himself that protect him; he gains 88 temporary hit points until the start of his next turn.

Hands of Dread (Costs 3 Actions). Azalin calls fourth four spectral hands of the Domains of Dread that targets 4 creatures he can see within 150 feet of him. Each creature targeted must succeed on a DC 22 Dexterity saving throw or take 24 (7d6) [psychic] damage and get pulled into a domain of dread for one round.