Depotheosis

This is one of the mightiest spells ever created, with the power to revoke an immortal's power. The caster spends five rounds saying the words and making the motions, and on the fifth action, they plunge a dagger into the heart of a humanoid or other creature they have an emotional bond with. As the creature dies, the power of the immortal leaves their body. This ritual only works if the caster knows the true name of the immortal and invoke it during the casting of the ritual. The immortal is now mortal and can be killed permanently like any other mortal.