Agnomakhos, Tyrant Eternal

Aura of Censorship. When a creature starts its turn within 30 feet of Agnomakhos, he can force that creature to make a DC 25 Wisdom saving throw if Agnomakhos can see it. On a successful save, the creature is immune to this aura for the next 24 hours. On a failed save, the creature can’t speak and is cannot cast spells that includes verbal components until the start of its next turn.

Divine Weapons. Agnomakhos's attacks with Ashen Blade are magical and treat immunity to damage as resistance instead.

Tyrant's Return (Mythic trait; Recharges after a Short or Long Rest). If Agnomakhos would be reduced to 0 hit points, his current hit point total instead resets to 550 hit points, he recharges his Conquer, and he regains any expended uses of Legendary Resistance. When Agnomakhos drops to 0 hit points or dies after Tyrant's Return activates, his essence is stored inside his Rod of Law and he is unable to take physical form for a time. 

Legendary Resistance (4/Day). If Agnomakhos fails a saving throw, he can choose to succeed instead.

Spellcasting. Agnomakhos casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 25):
At will: command, counterspell, detect thoughts
3/day each: circle of death, finger of death, modify memory
1/day each:  glibness*, heal, maddening darkness, power word: kill

*Agnomakhos casts glibness on himself before combat.

Multiattack. Agnomakhos makes three ashen blade or bolt of ash attacks.

Ashen Blade. Melee Weapon Attack:  +17 to hit, reach 10ft., one target. Hit: 28 (4d8 + 8) slashing damage plus 11 (2d10) necrotic damage. 

Bolt of Ash. Ranged Spell Attack: +17 to hit, range 120 ft., one creature. Hit: 32 (5d12) necrotic damage, and the target can’t regain hit points until the start of Agnomakhos's next turn.

Conquer (Recharge 5–6). Agnomakhos touches one creature within 10 feet of him. The target must succeed on a DC 25 Constitution saving throw or take 78 (12d12) necrotic damage and be weakened until the end of its next turn or half as much damage on a successful one. A weakened creature has disadvantage on Strength-based ability checks and Strength saving throws, and the creature's weapon attacks that rely on Strength deal half damage. On a successful save, the creature takes half as much damage and isn't weakened.

Eye of the Law. Agnomakhos targets a creature he can see within 60 feet of his and determines which laws that creature has broken in the last 24 hours.

Mount. If Agnomakhos isn't mounted, he can use a bonus action to magically teleport onto the creature serving as his mount, provided Agnomakhos and his mount are on the same plane of existence. When he teleports, Agnomakhos appears astride the mount along with any equipment he is wearing or carrying adding his mounts hit points to his own. While mounted and not incapacitated, Agnomakhos can't be surprised, and both it and his mount gain advantage on Dexterity saving throws.

Shapechange. Agnomakhos changes his size to medium and his weapon vanishes into the Nyx, while retaining his game statistics. While transformed in this way, Agnomakhos's creature type is humanoid.

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

Attack. Agnomakhos makes one Ashen Blade or Bolt of Ash attack.

Coordinated Assault (Costs 2 Actions). Agnomakhos makes one Ashen Blade attack, and then his mount can use its reaction to make a melee weapon attack.

Reduce to Ash (Costs 3 Actions). Agnomakhos targets a creature it can see within 60 feet of it. The target must succeed on a DC 25 Constitution saving throw, or it takes 52 (8d12) necrotic damage and its hit point maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the target finishes a long rest. If the target’s hit point maximum is reduced to 0, its body and everything it is wearing and carrying, except for magic items, are reduced to ash. A creature reduced to ash can’t be revived by any means short of a wish spell.

If Agnomakhos's mythic trait is active, he can use the options below as legendary actions.

Unending Conquest (Costs 2 Actions). Agnomakhos recharges and uses his Conquer ability.

Omen of Eternal Darkness (Costs 3 Actions). Agnomakhos becomes heavily obscured giving attacks against him disadvantage and turning light within 10 feet of him into magical darkness until the start of his next turn. A creature with darkvision can't see through this darkness. Non-magical light, as well as light created by spells of 8th level or lower, can't illuminate the area. While heavily obscured in this way, Agnomakhos gains a +2 bonus to his AC.