You summon 1 demon. You choose the demon's type, with a CR rating of 5 or lower. The demon appears in an unoccupied space you can see within range, and the demon disappears when it drops to 0 HP or the spell ends. Roll initiative for the demon, which has its own turns. You can issue a verbal command to it (no action). If you issue no command, it attacks any creature within reach that has attacked it. At the end of each turn, it makes a Cha save. The demon has disadv on this saving throw if you say its true name. On success, your control ends, and the demon pursues & attacks the nearest non-demons. If you stop concentrating on the spell before it ends, the demon doesn't disappear for 1d6 rounds if it still has hp. Optionally, when casting, you can form a circle on the ground with the spell's blood, encompassing your space. While the spell lasts, the demon can't cross the circle or harm it, and it can't target anyone within it.
When you cast this spell using a spell slot of 5th level or higher, the challenge rating increases by 1 for each slot level above 4th.
a vial of blood from a humanoid killed within the past 24 hours
Invito Daemon Maiorum