It is the very same site where Rayeld killed Nereza. Her corpse (and that of Sara) can be found in the center of the area. There is no interaction with them, but High Cleric's Journal tome can be found nearby. This location is accessed from Ancient Tower Study, after killing Fharzula. Forsaken Repose is an alternate version of the Battlements, accessible only through a purple portal from Testament of My Failure tomes.