Calamity

You may use a Bonus Action to remove the stitches from your mouth. If your mouth is unstitched, you may use an Action to speak Dark Speech.

Any creature who hears your voice must make a Constitution Saving Throw. Anyone farther than 60 feet from you, and anyone who keeps their ears covered the whole time beginning before you begin to speak, has advantage on the Saving Throw. Anyone within 20 feet of you, including yourself, has disadvantage on the Saving Throw. Each creature takes 14d6 necrotic damage on a failed save, or half as much damage on a successful save. If this damage leaves a creature with zero hit points, it is destroyed. Roll 1d10 and consult the Calamity Table to determine how the creature is destroyed. The fate of the soul of the creature is known only by the DM.

When you use this ability, you suffer 3 levels of exhaustion, some of your organs and/or body parts disappear, and your hit point maximum is permanently reduced by half as much as the necrotic damage that you take from it. This reduction to your hit point maximum can only be restored by means of a Wish spell or a spell that grants you an entirely new body, such as True Resurrection. You cannot use this ability again until all of your levels of exhaustion are removed.

Calamity Table:
1 - Mummification: the creature is dehydrated in a matter of seconds, and their corpse appears to have aged thousands of years.
2 - Disintegration: the creature instantly disintegrates to ashes.
3 - Incineration: the creature bursts into flames, which consume the creature entirely in mere moments.
4 - Compression: the creature convulses into the fetal position and then continues to be compressed as if crushed from all sides.
5 - Vaporization: the creature suddenly dissipates in a cloud of vapor.
6 - Liquefication: the creature suddenly devolves into a mass of green goop.
7 - Infestation: the creature is suddenly consumed from the inside out by a swarm of insects.
8 - Laceration: the creature suddenly suffers thousands of large cuts and collapses into a pile of diced flesh.
9 - Exsanguination: the creature suddenly bleeds from its orifices and vomits massive amounts of blood, collapsing in a pale heap in mere seconds.
10 - Evisceration: the creature is afflicted by the sudden disappearance of several organs and other body parts.