Destroy soul

An ancient spell crafted by a dark cult. The caster may destroy the soul of any target (alive or dead) within 10 ft. Caster take 10d10 necrotic damage, sacrificing part of their strength to darker powers. Target must remain within range for the entire casting duration of the spell. If the the casting target is alive, the soul of said target is destroyed although nothing seems to happen. Upon death the target is eternally erased from existence and does not have an afterlife. If target is dead, their soul is destroyed instantly and they are erased from whatever afterlife they are in. A target with a destroyed soul cannot be resurrected by any means, and is permanently dead upon reaching 0 hp. (no death throes, no waiting to reach double negatives).