Antioch, The Executioner

Atonement. Antioch whips himself with his Scourge of Atonement as a bonus action, reducing his hit point maximum by 18 (4d8). Until Antioch takes a short or a long rest all of his weapons attack deal an additional 17 (5d6) Fire damage and a creature must succeed on a DC 23 Constitution Saving throw or have their hit point maximum reduced by the amount of fire damage taken. This effect lasts until a creature takes a short rest.

Innate Spellcasting. Antioch's spellcasting ability is Charisma (spell save DC 20, spell attack +12). Antioch can innately cast the following spells, requiring no material components:
At will: message, sending, fireball, cure wounds (8th level), altar self
3/day each: teleport, dispel magic, hold monster, raise dead, wall of light, heal
1/day each: imprisonment, meteor swarm, harm (9th Level)

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

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

Magic Weapons. Antioch's weapon attacks are magical.

Penitent Nature. All reductions to Antioch's hit point maximum lose effect when he gains the benefits of a short or long rest.

Multiattack. Antioch makes three melee weapon attacks.

Judgement Blade. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 12 (1d8 + 7) Slashing damage. Antioch can move up to his movement speed without provoking opportunity attacks as part of making opportunity attacks with this weapon.

Scourge of Atonement. Melee Weapon Attack: +14 to hit, reach 30 ft., one target. Hit: 9 (1d4 + 7) Slashing damage. Antioch can force a creature hit with this weapon to succeed on a DC 20 Strength saving throw or be pulled up to 30 feet towards him. 

Antioch can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Antioch regains spent legendary actions at the start of their turn.

Relentless Pursuit (Costs 1 Actions). Move up to speed without provoking opportunity attacks.

Culling Strike (Costs 1 Actions). Makes one melee weapon attack.

Dimensional Lock (Costs 2 Actions). Antioch utters a condemnation, magically binding a creature to the current plane and preventing instantaneous travel. Antioch targets a creature within 120 feet of him. The target must succeed on a DC 23 Charisma Saving Throw or be unable to teleport or exit the current plane for 1 minute. 

Martyr of the Sinful. When Antioch drops to 0 HP for the first time, he kneels, impaling himself with his Executioner’s Sword while chanting a prayer. Golden fire erupts, burning away his remaining humanity — his armor blackens, his wings become molten bone, and his voice deepens. Antioch regains all hit points and gains the following benefits:

Regeneration. Antioch regains 20 hit points at the start of his turn. If he takes radiant damage, this trait doesn't function at the start of his next turn. Antioch dies only if he starts his turn with 0 hit points and doesn't regenerate.

Mythic Actions. Antioch gains access to additional legendary actions.

Flagellant’s Miracle (Costs 2 Actions). Antioch whips himself with his Scourge of Atonement reducing his hit point maximum by 18 (4d8), Antioch is then able to take the magic action as part of this legendary action.

Wings of Condemnation (Costs 2 Actions). Antioch takes flight with immense power. Each creature within 10 ft. of Antioch must succeed on a DC 20 Dexterity saving throw or take 8 (1d6 + 5) bludgeoning damage and be knocked prone. Antioch can then fly up to half his flying speed.