Artorias, The Abysswalker

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

Dark Weapon: Artorias's weapon attacks are magical. 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: +10 to hit, reach 5 ft., 1 target. Hit: 11 (2d6 + 4) slashing damage, plus 18 (4d8) necrotic damage.

Deeper Corriuption (1/Day): Artorias can allow the corruption of the Abyss to sleep 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 2 legendary actions, choosing from the options below. Only on legendary action can be used at a time and only at the end of another creatures turn. Artorias, the Abysswalker regains spent legendary actions at the start of its turn.

Greatsword: Enter the description for your legendary action.Artorias makes an attack with his greatsword.

Gripping Darkness (Costs 2 Actions): Enter the description for your legendary action.The Abyss leaks through Artorias's being, leaving a puddle in a 5 foot radius around him. Any creature that is in the puddle must make make DC 17 Deterity saving throw, takes 14 (4d6)  necrotic damage on a failed save, or half as much on a successful one. The puddle lasts for one round, after which it dissipates.