Legendary resistance(3day): If Zarythos fails a saving throw, he can choose to succeed instead.

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

Magic Weapons: Zarythos's weapon attacks are magical

Divine aura(mythic trait): when Zarythos is in mythic mode each creature within 60ft of him makes a DC 24 charisma saving throw or have disadvantage on attack rolls till the start of his next turn.

Multiattack: Zarythos makes 3 attacks with his blade of black sun.

Blade of the Black Sun: Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 31 (4d10 + 9) slashing + 22 (5d8) necrotic damage. If the target is reduced to 0 HP by this attack, they disintegrate into ash unless they are a god or demigod.

Judgement of the false dawn: Zarythos calls down a beam of black sunlight in a 60-ft radius, 100 ft high cylinder centered on a point he can see. Each creature in the area must make a DC 24 Con saving throw, taking 88 (16d10) radiant and 88 (16d10) necrotic damage on a failed save, or half as much on a success. Creatures killed this way can only be revived by a Wish or True Resurrection spell.

Zarythos can take 3 legendary actions, choosing from the options below. Only one can be used at a time and only at the end of another creature's turn.

• Command Fear. One creature within 60 feet must make a DC 24 Wisdom save or be frightened for 1 minute. Repeat the save at end of each turn.
• Shadow Step. Zarythos teleports up to 60 ft. to an unoccupied space he can see.
• Divine Smite (Costs 2 Actions). Makes a Blade of the Black Sun attack and deals an extra 27 (6d8) radiant damage.

   

• Chains of Judgment (Legendary Action - Costs 2)A radiant chain of divine order erupts from Zarythos and latches to a target's soul.Fail: 45 (10d8) radiant damage, and the creature is restrained by divine chains (save ends at end of each turn).If they die while restrained, their soul is bound to Zarythos's realm, and resurrection requires 

Black nova: when Zarythos is reduced to 50% hp he can use his traits labeled mythic trait and labeled mythic action

• Reality Sundering Strike (Mythic Action - 1/Day)Zarythos swings his blade and rips open the fabric of reality.Effect: A 120-ft long, 10-ft wide rift slices through the battlefield.Each creature in the line must make a DC 24 Constitution saving throw:Fail: 100 (20d10) force damage, 50 (10d10) psychic damage, and banishment to a random plane for 1 minute (save at end of each turn to return).Success: Half damage, no banishment.