Artorias the Abysswalker

Abyssal Bleed (Applied by other attacks). Dark energy forms where Artorias' attacks hit. A creature affected by abyssal bleed takes two damage at the end of its turn. This damage can stack, so that if a creature is affected twice, they will take four damage. This effect last until it is cured or Artorias is defeated (abyssal bleed can be removed with remove curse, greater restoration, or similar magic).

Agile Roller. As a bonus action Artorias can disengage.

Abyss Corrupted Armor. Critical hits against Artorias count as normal hits.

Wolf Ring. The ring grants outstanding indomitability. Outside forces are unable forcefully move Artorias.

Abyss Combustion. At 300, 200, and 100 hp, dark energy bursts from Artorias. Anyone within 30 ft. of Artorias makes a DC 19 Dex Saving throw. On a failed save they take 33 (6d10) necrotic damage or half as much on a success. Artorias' attack and damage bonus increase by one. His speed also increases by 10 ft. If multiple thresholds are met simultaneously the equivalent number of combustions occur at once. Applies Abyssal Bleed.

Legendary Resistance (3/day). If Artorias fails a saving throw he can choose to succeed instead.

Keen Accuracy (2/day). Artorias can give himself advantage on one attack roll.

Action Surge (1/day). Artorias gains an additional action on his turn.

Multiattack. The knight makes three greatsword melee attacks or one greatsword melee attack and one special attack.

Greatsword. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage. 

Special Attacks.

Agile slice (Recharge 5-6). Melee Weapon Attack: +14 to hit, reach 10 ft., all targets within range. Hit: 22 (4d6 + 8) slashing damage. Immediately after attacking, Artorias can jump up to 30 ft away without provoking opportunity attacks. Applies Abyssal Bleed.

Leaping Impale (Recharge 5-6). Melee Weapon Attack: +14 to hit, one target within 30 ft. Hit: 29 (6d6 + 8) piercing damage. Artorias jumps into the air and lands attempting to impale in the target. Applies Abyssal Bleed.

Petra Slice (Recharge 5-6). Melee Weapon Attack: +14 to hit, all creatures in a 20 ft line from Artorias. Hit: 36 (8d6 +8) slashing damage. Artorias dashes in a twenty foot line, striking all enemies within that line. Does provoke opportunity attacks. Applies Abyssal Bleed.

Whirlwind Slice (Recharge 5-6). Melee Weapon Attack: +14 to hit, reach 10 ft., all targets within range. Hit: 22 (4d6 + 8). Artorias spins twice with his greatsword stretched out. Make two attack rolls against each target within range. Applies Abyssal Bleed.

Parry. Artorias adds 5 to his AC against one melee attack that would hit it. To do so, the knight must see the attacker and be wielding a melee weapon.

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

Relentless. Artorias makes a greatsword attack.

Nimble. Artorias can use his movement.

Abyssal Energy. Artorias flings abyssal energy at a creature within 15 ft. They must succeed on a DC 19 Dex save or take 1d10 necrotic damage and be knocked prone. Applies Abyssal Bleed.

Demonic Strength (Cost 2 Actions). If the move isn't recharging Artorias can perform one of his special attacks; Agile Leap, Leaping Impale, Petra Slice, or Whirlwind Slice.