Tether

A Tether is a divine link between a mortal soul and their physical manifestation on the Material Plane or Mortal Realm. Created at birth, a Tether marks the beginning of consciousness for a creature, and does not fade over time. When the vessel chosen for a given soul can no longer carry it, the Tether is what pulls the soul and its memories back into the realms beyond, allowing it to experience a normal afterlife.
A Tether can be snapped before its time, using tools such as a Scythe or by a magic user's death curse, but this is often done only under dire need, as the resulting journey to the beyond can be less than ideal. Once a Tether has been snapped this way, the creature's soul and mortal vessel can only be rejoined by the will of deity, and few would do so without gaining Pharasma's ire. Even so, such mortals rarely recover from the trauma of having their Tether snapped, resulting in Insanity or severe memory loss.
It is said that an Alignmatist can manipulate a Tether, implying that they are similar in nature to Alignments, but their order is explicitly forbidden from sharing such knowledge with the public.