Captain of The Shadow

Innate Spellcasting. The abhorrent overlord’s spellcasting ability is Charisma (spell save DC 15). It can innately cast the following spells, requiring no material components:

At will: Bane, Entangle

4/day each: Arms of Hadar, Blindness/Deafness, Misty Step

2/day each: Black Tentacles, Blight

Multiattack. The captain makes two melee attacks with its scimitar.

Shadow Scimitar. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage plus one DC 13 Con Save for 9 (2d8) necrotic damage per round if any attack connects.

Storm of Souls (Recharge 5–6); The captain riles up all the lost souls on the ship. A swarm of souls made up of every race imagineable burst all throughout the ship. 

Any creature that is on, in, or within 20ft of The Shadow, must make a DC 15 Dexterity saving throw. A creature takes 16 (2d10) necrotic damage and is restrained on a failed save, or half as much damage on a successful one.

Parry. The captain adds 2 to its AC against one melee attack that would hit it. To do so, the captain must see the attacker and be wielding a melee weapon.

Uncanny Dodge. When an attacker that you can see hits you with an attack, you can use your reaction to halve the attack’s damage against you.

The captain can take 2 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 captain regains spent legendary actions at the start of its turn.

Throw Dagger  Ranged Weapon Attack: +5 to hit, range 20/60 ft., one target. Hit: 5 (1d4 + 3) piercing damage.

What Do We Do With a Drunken Sailor  Spectral ropes swing at a target trying to tie them up. Target surffers disadvantage on the next saving throw.