Agravain, Errant Knight of Iron

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

Spellcasting. Agravain's innate spellcasting ability is Itelligence (spell save DC 19, +8 to hit with spell attacks). It can innately cast the following spells, requiring no components:

At will: mind sliver, wrathful smite

6/day each: bane, misty step, nondetection (self only), command

3/day each: hold person, dispel magic, summon construct, confusion, tongues

1/day each: greater invisibility, mental prison 

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

Multiattack. Agravain makes two weapon attacks with his Improvised Halberd or with his Iron Commandments.

Improvised Halberd. Melee Weapon  Attack: +9 to hit, reach 10 ft., one target. Hit: 11 (1d10 + 6) slashing damage plus 9 (2d8) psychic damage. This is a magic weapon attack.

Iron Commandments. Range Weapon  Attack: +12 to hit, reach 90 ft., two target. Hit: 11 (2d6 + 5) piercing damage plus 7 (2d6) psychic damage. If the target is a creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained.This is a magic weapon attack.

Mad Enhancement. As an Bonus Action, Agravain can consume a vial of Mad Enhancement to boost his combat prowess at the expense of some of its mental capabilities. While under the effects of Mad Enhancement, Agravain gains the following benefits:

• He has advantage on Strength checks and Strength saving throws.
• He deals an extra 4 damage when he hits a target with a melee weapon attack (not included in attacks)
• He has resistance to all damage, but looses his Magical Resistance trait 
• His movement speed increases by 20 ft.
• He can make an additional melee weapon attack
• He cannot hold concentration on any of his spells

Hounds of Agravain. As an Bonus Action, and only if Agravain has currently Conjured a Metal Construct, he can transfer a vial of Mad Enhancement to boost its combat prowess at the expense of some of its mental capabilities. The construct gains the same effects described in the Mad Enhancement section.

Riposte. When a creature misses Agravain with a melee attack, he can use his reaction to make a melee weapon attack against the creature.

Agravain 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. Agravain regains spent legendary actions at the start of its turn.

• Attack. Agravain makes one weapon attack.

• He Who Knew No Wounds. Agravain casts one spell from his Innate Spellcasting list.

• Judgement. Agravain pulls in close to him all his enemies restrained by his Iron Commandments. Creatures restrained by Agravain's Iron Commandments must succed on a DC 17 Stenght check or be pulled up to 60 ft. close to Agravain. Immediately after, Agravain releases destructive wave. This spell targets Agravain as well.