Crystal Bound Soul

Your are a soul trapped. Created when a soul traveling through the Astral plane is forced back into the material via spell/ritual and is bound to a mineral.  The binder has the ability to influence/ control the bound soul. The bound project their form from the binding crystal and are connected to any crystals of the same mineral.  For example, one can project their form through a ring with the same material. Those bound loose any spell casting abilities they had previously including racial abilities. They gain access to sorcerers spells including specialty one based on properties of the mineral they are bound too. This variation is based on black agate, a black stone with white veins.  Spells revolve around light and dark...mostly dark. 

Revive

You can't permanently die until your binding stone is destroyed, or you are unbound.  If you fail all your death saves your body dispels for a time, (determined by dm) and then you can re-project.

Restful Release

You have the option at "death" to go into s a coma like state slowly releasing your life force into the the linked mineral until you pass. on...it takes 5 centuries.  It take's a special external ritual to be released from this state.  

Projection of Form

Since your soul is bound to a crystal you can project your form, unchanged from when you were bound through the same kind of crystals. You can also stop projecting at anytime, but it takes sometime before you can project again. There is no limit on time or distance you can project for, but the farther away from the binding stone the longer it takes to project. 

Telepathic link

You can talk to people telepathically if they are wearing a piece of the linked mineral, the person can respond but only if you're focusing on them. For example if they  have a pendant made out of the same kin do f stone as your binding stone you can talk with them.

Community of Stones

You can commune/talk with others like you.  When focusing you can find and talk to anyone else who is crystal bound.  Basically like hoping into a chatroom. 

Possession

You can take over the body and mind of a person wearing a piece of your linked mineral.  This lasts for an hour before you take 1 point of damage for each minute you are possessing the individual.