Souls provide the energy that Raziel needs to survive and progress through the game. Human and vampire souls can be acquired by destroying the creatures’ physical bodies. In addition, Raziel can suck soul energy out of non-combative humans without killing them. Lost souls can be found wandering the Spectral Realm, and are easy pickings for Raziel. Spectral enemies can be reduced to a vulnerable state through combat and then devoured.
These glowing balls of energy can be found throughout Nosgoth, in both the Material and Spectral Realms. This is the energy that Raziel must expend when a glyph is cast.