Trap Soul

You force a humanoid’s life force and its material body into a gem. Target one humanoid that you can see within 30 feet. The target must make a Charisma saving throw. Constructs and undead aren’t affected, on a failed save the target’s soul is magically trapped inside the gem. While the soul is trapped, the target’s body and all the equipment it is carrying cease to exist. On a successful save, the target takes 8d8 necrotic damage, and if this damage reduces the target to 0 hit points, its soul is trapped as if it failed the saving throw. Crushing the gem releases any soul trapped within, at which point the target’s body re-forms in an unoccupied space nearest to the gem and in the same state as when it was trapped.

While you have a soul inside the gem, you can exploit it in any of the ways described below. You may choose an alternative purpose for the soul such as using it to using to maintain a phylactery or using it as a component for crafting a magic item. The DM has final say on such alternative uses.

Devour Soul. If you're ever reduced to 0 hit points or die, you can use the trapped soul to restore yourself to life, if your soul is free and willing, with all your hit points. Using a trapped soul this way neutralizes any poisons and cures normal diseases afflicting you when you reached 0 hit points or died. It doesn't, however, remove magical diseases, curses, and the like; if such effects aren't removed prior to a trapped soul's use, they afflict the you on on return to consciousness or life. Using a trapped soul this way also closes all mortal wounds and restores any missing body parts. Using a trapped soul for this is devoured and ceases to exist.

Soul Inquisitor. You ask the soul a question (no action required) and receive a telepathic answer, which you can understand regardless of the language used. The soul knows only what it knew before being trapped, but it must answer you truthfully and to the best of its ability. You may use a trapped soul this way once every 8 hours.

Empowered Soul. You can use an action to bolster yourself with the soul’s life essence. Your spell attacks, spell saves, ability checks, saving throws, and initiative have advantage and attack rolls against you have disadvantage. This benefit lasts 8 hours or until dismissed with an action. Using a trapped soul for this is devoured and ceases to exist.

Eyes of the Damned. You can use an action to name a person or place the humanoid saw before being trapped, which creates an invisible sensor somewhere near the person or in that place if it is on the plane of existence you’re currently on. The sensor remains for as long as you concentrate, up to 20 minutes (as if you were concentrating on a spell). You receive visual and auditory information from the sensor as if you were in its space using your senses. You may use a trapped soul this way once every 24 hours.

A creature that can see the sensor (such as one using see invisibility or truesight) sees a translucent image of the tormented humanoid in a gem.