Tenebrae's Soul to Ether

This spell can only target the corpse of a sapient creature whose soul still resides within the body.

Upon completing this spell, you annihilate the creature's soul, breaking down the matrices binding its constituent ether together and releasing it all, optionally storing it within a dormant ether crystal if the crystal is used as a material component in the casting of the spell. Without a crystal to store it, the released ether disperses into the surrounding environment.

A creature whose soul is destroyed in this way can never be resurrected by any means short of divine intervention. However, their corpse can still be reanimated using necromancy.

Make an ability check using your spellcasting ability. The DC equals 10 plus the creature's Challenge Rating or Level. Success: You regain the spell slot used in the casting of this spell. You also gain a temporary spell slot of a level equal to half the creature's Challenge Rating rounded down, with a maximum of 6. This temporary spell slot disappears at the end of a long rest or once used, and cannot be used to cast Tenebrae's Soul to Ether. Failure: as the spell's effects go haywire, every creature in a 30-foot radius of the target takes (9d6) Force damage. The soul is still destroyed, but its ether cannot be stored in an ether crystal.

You may only gain a temporary spell slot from casting Tenebrae's Soul to Ether once per long rest.

Using a Higher-Level Spell Slot. If you succeed your saving throw, you may gain a temporary spell slot up to the level of the slot used to cast this spell. Also, for every level above 6th, when you fail the ability check, reduce the Force damage dealt by (3d6).