Artorias, The Abysswalker

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

Dark Weapon. When Artorias hits with his weapon, the weapon deals an extra (4d8) necrotic damage (included in the attack).

Multiattack. Artorias makes three greatsword attacks.

Greatsword. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage plus 18 (4d8) necrotic damage.

Deaper Corruption (1/day). Artorias can allow the corruption of the Abyss to seep deeper into his bones, making him stronger, faster, and tougher at the price of his sanity. When Artorias's hit points drop to 70 or lower, he gains a +4 bonus to attack and damage rolls, a +2 bonus to AC, and can move an additional 10 feet per round. During this time, he has disadvantage on all Intelligence, Wisdom, and Charisma checks and saving throws.

Leap Attack. When Artorias is targeted by an attacker who is within 30 feet, he can jump into the air, adding 2 to his AC against the attack, and land within 5 feet of the attacker. Artorias can then make an attack with his greatsword.

Artorias, the Abysswalker 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. Artorias, the Abysswalker regains spent legendary actions at the start of its turn.

Greatsword (Costs 1 Action). Artorias makes an attack with his greatsword.

Dripping Darkness (Costs 2 Actions). The Abyss leaks through Artorias's being, leaving a puddle in a 10-foot radius around him. Any creature that is in the puddle must make a DC 20 Dexterity saving throw, taking 14 (4d6) necrotic damage and becomes stunned on a failed save. On a successful save, the creature only takes half of the damage and isn't stunned. The puddle lasts for one round, after which it dissipates.

Wrath of the Abyss (Costs 3 Actions). Artorias draws upon the Abyss to punish his foes. All creatures within 30 feet of Artorias must make a DC 20 Dexterity saving throw, taking 55 (10d10) necrotic damage on a failed save. On a successful save, the creature only takes half of the damage. For the next minute after using this action, Artorias can make on additional attack per round and his melee weapon attacks deal one additional die of damage.