Caligrosto

Deflection. The caligrosto's AC includes its Charisma modifier.

Incorporeal Movement. The caligrosto can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Magic Resistance. The caligrosto has advantage on saving throws against spells and other magical effects.

Unusual Nature. The caligrosto doesn’t require air, food, drink, or sleep.

Innate Spellcasting. The caligrosto's spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). The caligrosto can innately cast the following spells, requiring no material components:

At will: crown of madness, enemies abound, invisibility, vampiric touch

Vampiric Touch. Melee Spell Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (3d6) necrotic damage and the caligrosto regains hit points equal to half the damage dealt.

Inhabit Weapon. The caligrosto disappears as it pours its psychic essence into a weapon that deals slashing damage it can see within 15 feet of it, magically possessing it. The object uses the caligrosto’s AC, and any damage dealt to the object applies to the caligrosto’s hit points. The caligrosto inhabits the object until it uses an action to leave; until it is turned; until it is reduced to 0 hit points; or until an effect that ends possession, such as a dispel evil and good spell, is used on it. When it leaves the object, it reappears in the nearest unoccupied space.

While inhabited, the weapon becomes a magic item if it wasn’t already, and a crack emitting a sickening red light appears somewhere it. Under truesight, the possessed weapon appears to be seething with coils of lightning-flecked mist. The caligrosto can cause the weapon to fly using the caligrosto’s own flying speed, use its senses, speak verbally or telepathically, and cast spells.

If a creature wields the weapon, the caligrosto can cause the weapon to behave as a Sword of Wounding. The caligrosto can pull the weapon from a creature's grasp with a successful Charisma (Intimidation) check contested by the creature's Strength check.