Multiattack. Adellaide makes two attacks, only one of which can be a bite attack.

Claw. Melee Weapon Attack: +5 to hit, reach 5ft., one creature. Hit: 6 (1d6 + 3) necrotic damage, and the target is grappled (escape DC 13).

Bite. Melee Weapon Attack: +5 to hit, reach 10 ft., one creature. Hit: 12 (2d8 + 3) necrotic damage and the target cannot regain hit points until the end of their next turn.

Bat-Away!  When taking damage that isn't radiant damage from a creature Adellaide can see, she melts into a cloud of bats and teleports to an unoccupied space she can see within 20 feet of her. When she does this, she gains resistance to one of the damage types that prompted this reaction, reducing the damage she takes in the process. She loses this resistance and regains her vampiric form at the start of her next turn.