"Archon of the Winter Sun, Sedris"

Aura of Death(1/day). Sedris can use his action to emit an aura of dark energy that extends 30 ft out from him. Necrotic energy pulses through the veins of nearby foes, causing them to rupture. For 1 minute any creature that starts its turn within the aura or enters it for the first time that turn immediately takes 14 (4d6) necrotic damage. Any healing that creature would recieve is halved and Sedris gains temporary hit points equal to the halved amount.

Regeneration. At the start of each of his turns Sedris regains 10 hit points if he has at least 1 remaining. 

One Against Many. When Sedris takes the attack action he can forfeit one attack to instead slam his axe into the ground causing dark blades to erupt from the ground hitting all creatures within 10ft of him.

Trinity of the Winter Sun. If sedris is killed he will revive at the next sunrise if both Thraximundar and Corvax are not killed before that time. On revival Sedris retains all items carried upon his death.

Fey Teleporation.(1/day) As a bonus action Sedris can teleport up to 120ft taking all his possessions with him.

 Inate Spell Casting. Sedris is 17th level spell caster, charisma is his spell casting ability with a DC of 19 and +11 to hit. Sedris has the following warlock spells innately imbued in him. (At will spells cast at 3rd level and 3/day spells cast at 5th level)

At will. false life, inflict wounds, vampiric touch

(3/day). shadow of moil, negative energy flood, blight

(1/day). Harm, Finger of Death, Abi-Dalzim's Horrid Wilting

Multiattack. Sedris makes two attacks with Skorn and uses earth shatter or casts a spell.

Skorn. Great axe attack: +11 to hit, reach 5 ft., 1 target. Hit: 19 (2d12 + 6) slashing damage and 10 (4d4) necrotic damage. The target must make a DC 19 constitution save, on a failure their max hp is reduced by the amount of necrotic damage they took. If this reduces a creature to 0 hp they die and skorn devours their soul. Sedris strength increases by 1 and he gains temporary hit points equal to half the creatures max hp.

Earth Shatter(recharge 6). Sedris drives his axe into the ground and the ground errupts in an explosion of ice and rock in a 30 foot cone emitting from the point of impact. Each creature in the cone must make a DC 18 dex save. On a failed save they take 10d6+6(40) cold damage and are stunned. On a success they take half damage. This attack cannot be used more than once per long rest.

Rise from the grave, to your knees. If a hostile creature falls to 0 hit points within 60 ft of Sedris they must roll a d20. On a roll of 19 or less they regain half of their total hit points and rise to their feet now at the mercy of their new master. Then can telepathically speak to Sedris up to a mile away and must obey every command given by him. If Sedris is killed while a creature is enthralled they must roll a d20, on a roll of 10 or less they lose their sanity and become a mindless zombie. On a success they fall unconscious then regain 1 hp.

Legendary resistance(3/day). If Sedris would fail a saving throw he may expend one use of his legendary resistance to succeed on the saving throw instead.

Sedris has 4 legendary actions and regains 2 at the start of every turn.

Vengeful Beast (Costs 1 Action). Sedris makes a melee attack with skorn with advantage.

Caress of Death(Costs 2 Actions). Sedris reaches out with his corrupted hand touching a creature within range. Make a melee spell attack, on hit the creature takes 13 (3d8) necrotic damage and is paralyzed for 1 minute. They may make a DC 19 constitution saving throw at the end of each of their turns or whenever they take damage to end the effect.

Death Pulse (Costs 3 actions). Sedris sends out a wave of pestilence in all directions from himself. Each creature within 20 ft must make a DC 19 constitution save or take 21 (6d6) necrotic damage and become poisoned, or half as much on a success and are not poisoned.

Army of the Damned (Costs 4 Actions). Sedris summons 7 (1d4 + 6) ghouls within a 30 ft radius around himself. If their are any dead creatures in the radius raise them instead.