The Keeper Compound is an otherwise invisible area within the City, that can be seen and entered only by Keepers' allies and the Keepers themselves. It is explored in Thief: Deadly Shadows as Garrett works closely with the Keepers to apprehend the coming 'Dark Age'.
After the Final Glyph has been activated, the Keeper Compound is revealed for all to see, and the resident Keepers disappear.
Keepers and scribes stay in its living quarters, constantly learning how to use Glyph magic and spells. Scribes must also learn to control the Glyphs.