The Lost is a dead deity spoken of in some stories recorded by followers of Malavisch. The former existence of the god is a matter of intense theological dispute and disagreement amongst devotees of other Chaskan deities, as the notion of gods having already met their end is heretical to most.
Even to those that believe that the Lost once existed, almost nothing is known about the god. They are presumed to have had a proper name at one point, but if they did it has been lost to time, as have their areas of concern, holy symbol, and effectively every other characteristic that could identify the deity.
Malavischan account
As the first creation was coming into form, Malavisch is said to have cleverly negotiated a contract with the Lost, agreeing to serve as his arbiter and deputy to oversee the newly-created inhabitants of the universe. In exchange, he would inherit the Lost's domains upon the god's death. Of course, the Lost agreed - he was divine, and he believed he could not die in any way that mattered. But Malavisch knew otherwise. He had seen Lotan lurking in the primordial chaos, and he knew an attack was inevitable. When Lotan finally struck at Socharin, his anger too great to possibly contain, the Lost and Malavisch joined the other gods in driving Lotan back to the void. Malavisch and his superior fought back to back, protecting each other and striking as one. At least, until Malavisch vanished, knowing his contract did not require him to defend the Lost. Left alone, the Lost could not endure Lotan's attacks. He was consumed, struck from existence, his domains going to Malavisch as the contract was fulfilled.