Archon of Coronation

Aura of Suggestion. When a creature starts its turn within 30 feet of the archon, she can force that creature to make a DC 18 Wisdom saving throw if she 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 forced to kneel until the start of its next turn.

Innate Spellcasting. The archon's spellcasting ability is Wisdom (spell save DC 18). The rider can innately cast the following spells, requiring no material components:

At will: command, compelled duel, crown of madness

1/day each: banishment, blade barrier

Mount. If the archon isn’t mounted, it can use a bonus action to magically teleport onto the creature serving as its mount, provided the archon and its mount are on the same plane of existence. When it teleports, the archon appears astride the mount along with any equipment it is wearing or carrying.

While mounted and not incapacitated, the archon can’t be surprised, and both it and its mount have advantage on Dexterity saving throws. If the archon is reduced to 0 hit points while riding its mount, the mount is reduced to 0 hit points as well.

Multiattack. The archon makes three attacks with its lightning trident or two attacks with its bolt of lightning.

Lightning Trident. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) slashing damage plus 13 (2d12) lightning damage.

Bolt of Lightning. Ranged Spell Attack: +10 to hit, range 120 ft., one creature. Hit: 22 (4d10) lightning damage, and the target is knocked prone.

The archon of coronation 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 archon regains spent legendary actions at the start of its turn.

Attack. The archon makes an attack using its lightning trident or bolt of lightning.

Coordinated Assault (Costs 2 Actions). The archon makes an attack using its lightning trident or bolt of lightning, and then its mount can use its reaction to make a melee weapon attack.

Reduce to Ash (Costs 3 Actions). The archon targets a creature it can see within 60 feet of it. The target must succeed on a DC 18 Constitution saving throw, or it takes 27 (5d10) lightning damage and its hit point maximum is reduced by an amount equal to the lightning 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.