Codricuhn, the Blood Storm

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

Innate Spellcasting. Codricuhn's spellcasting ability is Charisma (spell save DC 19). He can innately cast the following spells, requiring no material components:

At Will: detect magic, lightning bolt

3/day each: dispel magic, hellish rebuke (5th Level), maelstrom, 

1/day: summon greater demon (9th level), power word pain

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

Magic Weapons. Codricuhn's attacks are magical.

Siege Monster. Codricuhn deals double damage to objects and structures (included in Bloodwave).

Multiattack. Codricuhn uses his Frightful Presence. He can then make two attacks, only one of which may be his Exsanguination attack.

Exsanguination. Codricuhn targets one creature he can see within 120 feet of him. That creature must succeed a DC 19 Constitution saving throw or suffer 29 (3d12 +10) necrotic damage as blood begins to be forced from its pores and orifices, or half damage on a successful save. A creature who fails this save by 5 or more spends its turn retching blood and cannot take actions or reactions. 

Whether the creature succeeds or fails, Codricuhn heals by half the necrotic damage dealt by this attack.

Frightful Presence.  Each creature of Codricuhn's choice that is within 120 of him and and aware of him must succeed a DC 19 Wisdom Saving throw or become frightened for 1 minute. A creature can repeat its saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Codricuhn's Frightful Presence for the next 24 hours.

Fist. Melee Weapon Attack: +16 to hit, reach 20 ft., one target. Hit: 22 (2d12 + 10) bludgeoning damage plus 6 (1d12) fire damage.

Bloodwave (Recharge 6). Codricuhn creates a wall of blood centered on himself. The wall is up 250 feet long, up to 250 feet high, and up to 50 feet thick.

When the wall appears, all other creatures within its area must each make a DC 24 Strength saving throw. A creature takes 33 (6d10) bludgeoning damage plus 5 (1d10) fire damage on failed save, or half as much damage on a successful one.

At the start of each of Codricuhn turns after the wall appears, the wall, along with any other creatures in it, moves 50 feet away from Codricuhn. Any Huge or smaller creature inside the wall or whose space the wall enters when it moves must succeed on a DC 24 Strength saving throw or take 27 (5d10) bludgeoning damage plus 5 (1d0) fire damage. A creature takes this damage no more than once on a turn. At the end of each turn the wall moves, the wall’s height is reduced by 50 feet, and the damage creatures take from the wall on subsequent rounds is reduced by 1d10. When the wall reaches 0 feet in height, the effect ends.

A creature caught in the wall can move by swimming. Because of the force of the wave, the creature must make a successful DC 24 Strength (Athletics) check to be able to move.

Codricuhn 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. The leviathan regains spent legendary actions at the start of its turn.

Fist. Codricuhn makes one fist attack.

Move. Codricuhn moves up to his speed.

Blood Dominion (Costs 3 Actions) Codricuhn targets one creature he can see within 120 feet. That target must succeed a DC 19 Wisdom saving throw. On a failed save, Codricuhn controls that creatures actions, bonus actions, movement, and reactions until the end of that creature's next turn. Codricuhn gains full knowledge of all the creature's abilities,  but not of their equipment, thoughts, or memories.

Cordricuhn can maintain this dominion only until the end of his next turn.

A creature who succeeds its saving throw or who is freed after the effect ends is immune to this effect for 24 hours.