Avadon, The Despoiler

Balefiend (1/Turn). When Avadon hits a creature with a melee weapon attack, he can choose to deal an additional 1d4 damage to it. The next attack roll the creature makes is reduced by an amount equal to what Abbadon rolled on the d4.

Devil's Sight. Magical darkness does not impede Avadon's dark vision.

Pride's Pursuit (1/Turn). When Avadon misses a creature with a weapon attack, he can immediately make another weapon attack against it.

Magical Weapons. Avadon's weapon attacks are magical.

Innate Spellcasting. Avadon's spellcasting ability is Charisma (spell save DC 19, +11 to hit with spell attacks). Avadon can cast the following spells, requiring no material components:

At Will: Darkness, Eldritch Blast (4 Beams), Mage Hand

1/Day Each: Bane, Dominate Person, Hex, Hellish Rebuke, Counterspell, Mirror Image, Blight, Banishment, Hold Monster, Plane Shift

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

Multiattack. Avadon makes two Greatsword attacks.

Greatsword. Melee Weapon Attack: +11 to hit, reach 10 ft., 1 target. Hit: 18 (4d6 + 6) slashing damage, plus 6 (2d6) fire damage.

Bonds of Torment (Recharge 5-6). Avadon conjures magical spiked chains that lash out at a creature he can see within 30 feet of him. The creature must make a DC 19 Dexterity saving throw. On a failure, the creature takes 24 (8d6) piercing damage and is restrained. A creature that is restrained this way cannot teleport or use interplanar travel and takes 9 (3d6) piercing damage at the start of each of its turns. A creature that succeeds on the initial saving throw takes half as much damage and is not restrained.

As an action, a creature can make a DC 19 Strength (Athletics) or Dexterity (Acrobatics) check. On a success, the creature escapes and the chains disappear.

Summon Fiend (1/Day). Avadon magically summons a fiend of CR 8 or lower. The summoned fiend appears in an unoccupied space within 60 feet of Avadon. It remains for 1 hour or until it drops to 0 hit points. The fiend goes right after Avadon in the order of initiative. The fiend is friendly towards Avadon and obeys his spoken commands.

Pernicious Spike (Recharge 5-6). Melee or Ranged Spell Attack: +11 to hit, reach 10 ft. or range 30 ft., one target. Hit: 6 (2d6) poison damage, and the target must succeed a DC 19 Constitution saving throw or be poisoned for one minute. While poisoned this way, the target cannot regain hit points. The target can reattempt the saving throw at the end of each of its turns, ending the effect on itself on a success.

Parry. Avadon adds 3 to his AC against a melee attack that would hit him. To do so, he must be able to see his attacker and be wielding a melee weapon.

Avadon 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. Avadon regains spent legendary actions at the start of his turn.

Attack. Avadon makes a Greatsword attack or casts Eldritch Blast.

Fiendish Magic (Costs 2 Actions). Avadon uses Spellcasting.