The Mortal Coil
The Mortal Coil is the world as we know it. Everything in the cosmos is a byproduct of something originating from the Mortal Coil though it is unclear whether gods created it originally or if it simply was.
The Ith
The Ith is a dream world that is shaped by every thought or emotion ever felt by beings on the Coil. It is a strange realm that mortals are only aware of by its direct association with magic. Only brief glimpses of the Ith by mages of legendary status have allowed mortals to accept the Ith as a reality and those that have seen it can only describe it as a mass of swirling white fog containing half formed shapes both glorious and horrifying. Though the Ith is extremely hard for Mortals to affect, the Ith influences every creature in existence and sometimes manifests in a physical form. This substance, know as Tass, or Essence of the Gods in the Old Tongue, is the staple form of magical power and is used in the creation of magic items.