Archduke Levistus of Stygia

Death Throws.  When Levistus’ hit points drop to 0, he explodes and each creature within 40 feet of him must make a DC 25 Dexterity saving throw taking 68 (8d10) cold damage on a failed save, or half as much on a success. Levistus' essence then travels back to his castle in Stygia and is unable to take physical form for a time.

Devil’s Sight. Magical darkness doesn’t impede Levistus’ darkvision.

Innate Spellcasting. Levistus' innate spellcasting ability is Charisma (spell save DC 26, to hit +15). He can innately cast the following spells, requiring no material components:

At will: misty step, major image, sleet, storm, water walk

3/day each: counterspell, hold monster, maelstrom, scrying

1/day each: power word kill, tsunami, wall of thorns (9th level, summons bones instead of thorns, no mechanical difference, except bone devils take no damage and are not slowed moving through the wall)/

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

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

Stygian Depths. When Levistus uses water in a spell, ability, or effect it causes an extra 22 (4d10) cold damage. every round a creature targeted by the spell or ability is in contact with the water. A creature that take the cold damage must also make a DC 28 wisdom save or be under the effects of a confusion spell for 2 (1d4) rounds. A creature can only suffer the confusion effect once per day.

Cruel Necessity. Cruel Necessity is +4 epic rapier that deals an extra 14 (3d8) damage when wielded by Levistus, included in the attack.

Icy Tomb. Levistus is currently imprisoned in a large mass of Stygian ice a minimum of 20 feet thick. While imprisoned his ability to take actions is extremely limited. He can only communicate telepathically and he cannot take any physical actions. He can, through sheer will, move the ice1 foot per round. In addition, he can cast the following spells while entombed: charm person, major image, counterspell, dominate monster, hold monster, power word kill, scrying, and wish

However, the ice does block line of effect for spells and ranged attacks. In addition, each 5 feet of ice has AC 15 and 100hp and regenerates 20 hp of ice per round and anyone within 10 feet of the ice must make a DC 25 Constitution saving throw, taking 55 (10d10) cold damage on a failure and half as much on a success. The ice is vulnerable to fire.

Multiattack. Levistus makes four cruel necessity or chilling touch attacks.

Chilling Touch. Melee Weapon Attack: +15 to hit, reach 5ft, one target. Hit: 22 (4d10) cold damage and must make a DC 24 Constitution saving throw or be paralyzed for one minute. The creature may repeat this save at the end of their turn, ending the effect on a successful save.

Cruel Necessity. Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 34 (4d8 + 16) piercing damage.

Icy Glare. Ranged Spell Attack: +15 to hit, range 240ft., one target Levistus can see. Hit: 55 (10d10) cold damage and the target must make a DC 24 Constitution saving throw. On a failed save the creature begins to turn to ice and is restrained. It must repeat the saving throw at the end of its next turn. On a success it takes 22 (4d10) cold damage and the effect ends. On a failure the creature is turned to ice (petrified, but no change in weight and no resistance to damage except immunity to cold) until freed by a greater restoration spell or similar magic.

Elaborate Parry. Levistus focuses his efforts on an impenetrable defense and gains a +4 bonus to his armor class and gains an extra reaction for 1d4 rounds.

Disarming Strike. When Levistus uses cruel necessity and hits a creature wielding a weapon he can choose to spend his bonus action and attempt to disarm the target. The creature must make a DC 24 Dexterity or Strength saving throw or drop their weapon.

Infernal Summons (3/day). Levistus magically summons (100% chance of success) 1d8+4 bone devils, 1d4 ice devils, or (50% chance of success) one of his Dukes.

Master Footwork. When Levistus is hit with a weapon attack he can spend his reaction and gain a +4 bonus to his AC. If the hit becomes a miss he can redirect the attack to another target of his choice within the attacks range.

Evasion. If Levistus succeeds on a saving throw and would suffer damage or an effect; he can spend his reaction to take no damage or effect.

Levistus 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. If Levistus has unspent legendary actions at the end of the round, he may spend and immediately use his remaining legendary actions. Levistus regains spent legendary actions at the start of its turn.

Attack. Levistus makes a cruel necessity or chilling touch attack.

Parry. Levistus gains a +2 cumulative bonus to his armor class until the start of his next turn. This stacks with evasion.

Cast a Spell (1/round). Levistus casts a spell.

Glare (Cost 2 actions). Levistus makes and icy glare attack.

Teleport (Cost 2 actions). Levistus magically teleports along with anything is carrying up to 120 feet to an unoccupied space his can see.