Immutable Form. Abysswalker is immune to any spell or effect that would alter its form.

Legendary Resistance (3/Day). If the Abysswalker fails a saving throw, it can choose to succeed instead.

Resilient Body. The Abysswalker takes 1d6 reduced damage from all magical or non-magical sources. If the source utilizes radiant damage, add 1d6 damage to the final damage roll.

Limited Spellcasting. The Abysswalker's spellcasting ability is Wisdom (spell save DC 14). It can innately cast the following spells, requiring no material components:

At will: Dark
2/Day each: Darkra (Activation Required- Screams of Lea Monde)
2/Day each: Darkga (Activation Required- Screams of Lea Monde)
1/Day: Eternal Darkness

Multiattack. The Abysswalker can perform up to three actions. Usage of Grasp of the Void must be preceded by the execution of Shadow Sneak.

Ultima Blade. Melee Weapon Attack: +15 to hit, reach 5 ft., 1 target. Hit: 29 (4d12 + 10) slashing damage. 

Claws of Lea Monde. Area Melee Attack: +15 to hit, range 20 ft cone. Hit: 29 (2d12 + 10) slashing damage and (3d4+2) necrotic damage.

Shadow Sneak. (Recharge 6) The Abysswalker vanishes into shadow, appearing in an unoccupied space within 25 ft that is adjacent to a hostile creature. This ability must be followed up be Grasp of the Void.

Grasp of the Void. This action can only be executed following Shadow Sneak. The Abysswalker appears behind its target and attempts to pull them into its veiled shadows. The target must make a Contested Strength check and take 32 (8d8) necrotic damage and become restrained to the Abysswalker on a failed save. The target is not restrained on  a successful save, but will still take 24 (6d8) necrotic damage.
Restrained targets can attempt to break the restraints at the start of their turn by rolling a Strength saving throw (DC 22) as their only action. This save DC will decay by 4 points each subsequent turn, hitting a minimum limit of DC 10 after 3 failed attempts as the shadows binding them begin to disperse.

Screams of Lea Monde. The Abysswalker can cast one spell as a bonus action per turn. Spells must be utilized in sequential order, as the Abysswalker's rage grows per turn. Dark to Darkra to Darkga over the course of three turns.

Eternal Darkness. The Abysswalker can cast Eternal Darkness as a bonus action per turn. This spell can only be utilized after expending all charges of Darkga casts.

Shield of Darkness. (5/Day) The Abysswalker can coalesce shadow into a protective barrier, increasing their AC by +3 for one incoming attack.

Abysswalker, Sabik's Darkness 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. The Abysswalker regains spent Legendary Actions at the start of its turn.

Void's Hunger (Costs 2 Actions). The Abysswalker roars, sending unrestrained energy about in reckless abandon. The Abyss walker can target up to two auracite shards within 30 ft and consume them, granting 2d8 healing per shard absorbed and empowering the Abysswalker with a shield reducing damage from magical attacks by 1d8 damage per shard absorbed.

Offer Vitality (Costs 1 Actions). The Abysswalker releases a portion of its stored vitality onto the Virgo Demon, providing the demon with 6d10 healing while subtracting that amount from the Abysswalker's own lifeforce. If the Abysswalker has a target restrained from Grasp of the Void currently, they can supplement 3d10 of the healing by siphoning the life force of its prisoner.

Shadows of Lea Monde (Costs 3 Actions). The Abysswalker calls out to the latent energy of the destroyed capital of Lea Monde, as darkness takes root and pools at your feet. An area with a radius of 15 ft of the Abysswalker becomes twisted by the darkness, creating difficult terrain for two rounds and dealing 2d4 necrotic damage to all non-undead at the start of their turn or when entering the area. All damage dealt to creatures within this space heals the Abysswalker for that same amount.