Amorphous. Acleus can move through a space as narrow as 1 inch wide without squeezing.

Shadow Stealth. While in dim light or darkness, the shadow can take the Hide action as a bonus action.

Sunlight Weakness. While in sunlight, Acleus has disadvantage on attack rolls, ability checks, and saving throws.

Enveloping Darkness: Once per long rest Acleus can envelop a creature in total darkness. While in sunlight they can cover a creature no larger than normal, in artificial lighting no larger than Large, in complete darkness no larger than Huge. 

Night Armor: Acleus transforms into an suit of Dark Matter Armor. Acleus wraps itself around the user giving them an AC of 20 for 60 seconds (10 rounds). Anytime an attack doesn’t hit, the attacker will be repelled the creature must make a DC 14 constitution check. On a failed save the creature will take 1d10 [Force] Damage. On a successful save the creature will take half damage. 

Strength Drain. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 9 (2d6 + 2) necrotic damage, and the target's Strength score is reduced by 1d4. The target dies if this reduces its Strength to 0. Otherwise, the reduction lasts until the target finishes a short or long rest.

If a non-evil humanoid dies from this attack, a new shadow rises from the corpse 1d4 hours later.