Tor’s Devilish Binding

You find a fiend, it attempts to (determined by your dm) and in return, you cast Fiendish Binding. You hold the skull in your off hand, your main hand holds the horn. The blood from the horn drips onto your hand. You begin to chant the spell, the chain glows, it becomes of pure energy, and it wraps around the neck of the fiend. The fiend’s shadow disappears, signaling that it is now bound to your control permanently. You can only use this spell once. If you use this spell again on a different fiend, the other fiend will gain freedom, and will kill you. You will have to roll a saving throw of intelligence. If it is above 10, the spell is successful. If it is below ten, the spell fails and the fiend gains anger. The spell only works on Imps, Lemures, Bearded Devils, Nupperibos, Spined Devils, Chained Devils, Bone Devils, and Homebrew Devils.