Vampire Weaknesses. The vampire has the following flaws: Forbiddance. The vampire can't enter a residence without an invitation from one of the occupants. Harmed by Running Water. The vampire takes 20 acid damage when it ends its turn in running water. Sunlight Hypersensitivity. The vampire takes 20 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks. Incorporeal Movement. The vampire 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.
Blood Swarm. Spell attack. +6 to hit. One target, 5 ft. Hit: 6 (1d6 + 3) piercing damage plus 7 (2d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. Possession (Recharge 6). One humanoid that the vampire can see within 5 feet of it must succeed on a DC 13 Charisma saving throw or be possessed by the vampre; the vampire then disappears, and the target is incapacitated and loses control of its body. The vampire now controls the body but doesn't deprive the target of awareness. The vampire 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 immunities. The target does gain the weaknesses of the vampire. It otherwise uses the possessed target's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies. The possession lasts until the body drops to 0 hit points, the vampire ends it as a bonus action, or the vampire is turned or forced out by an effect like the dispel evil and good spell. When the possession ends, the vampire reappears in an unoccupied space within 5 feet of the body. The target is immune to this vampire's Possession for 24 hours after succeeding on the saving throw or after the possession ends.
Reactive Possession. When the vampire is hit with a melee attack it can use its possession ability if it is recharged.