The Last Word of the Unbent

You enter a round chamber of cracked white stone, where old banners hang in strips from a ceiling lost in darkness. A black altar crouches at the center beneath a dead knight's statue. Its stone face has no eyes, only a jagged mouth. Three sockets mark the altar: a mouth, an eye, and an open hand. A bronze mask rests nearby, an iron bowl waits beneath it, and three chained plaques bear fragments of an oath. The sealed door at the far wall gives a low, patient throb, as if something behind it is listening.