Echoes of Eternity
A soul is an invisible and intangible influence which usually pilots the body of a sufficiently advanced mortal organism. Souls can retain memories and even entire personalities, though how easy it can be to access these or to interact with a soul at all varies based on circumstance.
It is said that mortal souls are innately linked to the Gods of legend. The mortal races of Foleris currently understand little more than this about the nature of souls.