Voulgarghas
CREATURE 21Variant male bdellavritra
Masters of possession, bdellavritras enact complex schemes through pawns in the mortal world. Even if expelled from their hosts, these fiends retain fearsome physical strength with bodies that bely their agility.
A monster with telepathy can communicate mentally with any creatures within the listed radius, as long as they share a language. This doesn't give any special access to their thoughts, and communicates no more information than normal speech would.
The monster can cast its at-will spells any number of times without using up spell slots.
A constant spell affects the monster without the monster needing to cast it, and its duration is unlimited. If a constant spell gets counteracted, the monster can reactivate it by spending the normal spellcasting actions the spell requires.
3d8+9 bludgeoning plus 2d6 cold, DC 41 basic Fortitude
The monster deals the listed amount of damage to any number of creatures Grabbed or Restrained by it. Each of those creatures can attempt a basic Fortitude save with the listed DC.
Critical Success The creature is unaffected.
Success The creature takes half damage and is Stupefied 1 for 1 round.
Failure The creature takes full damage, gains weakness 10 to cold, and is stupefied 1 for 1 minute.
Critical Failure The creature takes double damage, gains weakness 15 to cold, and is Stupefied 2 for 1 minute.
The bdellavritra spends 10 minutes adjacent to an Unconscious or willing living creature, then attempts to possess its body. This functions as Possession heightened to 9th rank (DC 37 Will save), except that it has a duration of 1 month. If affected, the host receives new saving throws only at the start of each day. If the host dies, the bdellavritra must attempt a Fortitude save as normal but is only Stunned 2 on a failure (or Stunned 4 on a critical failure).
The monster can instead use Improved Grab as an action and choose one creature it's grabbing or restraining with an appendage that has Improved Grab to automatically extend that condition to the end of the monster's next turn.