Blood Shade

Sanguine Restoration. When the blood shade damages an enemy, it regains a number of hit points equal to half of the damage dealt.

Bloodletting. If a creature the blood shade is in possession of takes 30 or more damage in a single attack, the shade must make a Charisma saving throw with a DC equal to half of the damage, rounded down. 

Liquid Form. The shade ignores difficult terrain and can move through small holes and narrow spaces larger than an inch. It treats running water as difficult terrain, and if it ends its turn inside running water, it takes 1d8 cold damage. 

Crimson Strike. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) necrotic damage. 

Stain. Ranged Weapon Attack: +6 to hit, range 30/90 ft., one target. Hit:  17(2d10 + 6) necrotic damage. If this attack hits, the target must make a DC 16 Wisdom saving throw. On a failure, the target is Stained. The blood shade has advantage on its next attack against the target, and the target has disadvantage on its next attack against the blood shade. 

Arterial Bridling (Recharge 6). One humanoid that the shade can see within 5 feet of it must succeed on a DC 14 Charisma saving throw or be possessed by the shade; the shade then disappears, and the target is Incapacitated and loses control of its body. The shade now controls the body but doesn't deprive the target of awareness. The shade can't be targeted by any attack, spell, or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened. It gains access to the body's knowledge for the time that it is possessing the body, as well as the body's proficiencies. 

The possession lasts until the body drops to 0 hit points, if 1 minute has passed, or if the shade ends it as a bonus action. Possession can also end if a Dispel Evil and Good spell or similar is cast on the possessed target. When the possession ends, the shade reappears in an unoccupied space within 5 feet of the body. The target is immune to this shade's Possession for 24 hours after succeeding on the saving throw or after the possession ends.

Find Bloodstain. The blood shade can use a bonus action to teleport to a Stained target within 60 ft.