Marilith

Mariliths are demons who often serve as captains in Abyssal hordes.

Appearance
Mariliths have the torso and head of a humanoid woman, and the lower body of a snake. They have six arms and often wield a sword in each hand. They are also excellent tacticians.

Abilities
Mariliths, in addition to their prowess in combat, can communicate telepathically to creatures within 120 ft. They are resistant to magic, can attack and grapple with their tails, and are capable of teleporting short distances.

Vox Machina Origins Series I
Vox Machina encountered and fought a marilith named Iselda in Stilben.