Variant: Summon Demon
The demon chooses what to summon and attempts a magical summoning.
A vrock has a 30 percent chance of summoning 2d4 dretches or one vrock.
A summoned demon appears in an unoccupied space within 60 feet of its summoner, acts as an ally of its summoner, and can't summon other demons. It remains for 1 minute, until it or its summoner dies, or until its summoner dismisses it as an action.