Oblivion

Oblivion is the boundary between the rest of the planes and total annihilation. It is often used to refer to both the gateway and the total lack of existence beyond it, though there is an important difference between the two.   Oblivion as a gateway is more or less the twilight zone between existence and non-existence. Souls that could be resurrected or serve some magical function but have no other place to go are frozen in stasis here, along with the shadows of all that is lost forever.   This is where Kobolds, Starspawn, Cephapeople, Vesper, and Sentient Sharks go after they die, along with all other creatures not explicitly destined for Paradise, Purgatory, the Cat Heavens, or the Moonlands.   Oblivion isn't somewhere people travel to, generally. Those who do use planar travel spells to venture here never return. Attempts to magically detect into this place return only with a sense of infinite restful void. To physically enter Oblivion is to die and enter an endless and timeless slumber.   Oblivion is just the sensation and threshold of non-existence, though. Souls can be beckoned back from it without having to be entirely reconstructed and certain spells can draw on the knowledge of souls here at the boundary. When a soul or thing here has no possible way of being used in any other plane and is beyond the touch of any last magic, it slips through the gate and out of this world entirely.   What exactly happens to souls that slip beyond oblivion is unknown. Many reasonably assume that those souls are unmade and experience nothing. Others believe that there are worlds beyond this one and that there are afterlives beyond those that The Architects created.   In essence, Oblivion is the timeless sleep that precedes the true and original experience of death, unimpeded by the divine meddling of the Architects. Not even the Architects know what lies beyond.   The only known "entrance" to Oblivion is in the Astral Plane, but that is more of a hazard that a travel destination.