Armageddon

 You consume half of the blood in the chalice, and pour the other half onto the demon skull, binding you to the abys. This binding allows you to summon a demon within 10’ of you every round.  The demon must succeed a wisdom saving throw or be under you control until the spell ends or they die. After summoning 1d6+spell casting bonus(the GM rolls, doesn’t tell you the number) demons, the next one summons will be a demon prince, who automatically succeeds the save, and will stay, even if the spell is dispelled. The demon prince will target the caster first, then anyone nearby, until there is no one within 120’ of it. It will then begin opening a portal to the abyss, starting an infestation.