You cause a creature to feel magical calmness and make them fall asleep. One round later they become a servant; they gave in to your magic. Then the effects happen:
The creature has to make a Wis save of 15 or fall asleep.
On fail, the creature falls asleep and becomes unaware of everything. Then, the creature wakes up, and you can give it telepathic orders.
On critical fail, the creature falls asleep and takes 1d4 phycic Damage. Then, the creature wakes up, and you can give it telepathic orders.
On success, the creature can make a Wisdom (perseption) check to find where the spell came from.
On critical success, the creature knows were you are and gains first attack.
On Critical success, this does not happen:
After the spell ends, (and the creature is dead) the creature can make a Con saving throw of 20 to become a Revenant.