Source: Unearthed Arcana 11 - That Old Black Magic
4th-level conjuration
Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a vial of blood from an intelligent humanoid killed within the past 24 hours)
Duration: Concentration, up to 1 hour
You summon a shadow demon that appears in an unoccupied space you can see within range. The shadow demon disappears when it drops to 0 hit points or when the spell ends.
Roll initiative for the shadow demon, which has its own turns. You can issue orders to the shadow demon, and it obeys you as long as it can attack a creature on each of its turns and does not start its turn in an area of bright light. If either of these conditions is not met, the shadow demon immediately makes a Charisma check contested by your Charisma check. If you fail the check, the spell no longer requires concentration and the demon is no longer under your control. The demon automatically succeeds on the check if it is more than 100 feet away from you.
As part of casting the spell, you can scribe a circle on the ground using the blood of an intelligent humanoid slain within the past 24 hours. The circle is large enough to encompass your space. The summoned shadow demon cannot cross the circle or target anyone in it while the spell lasts.