Maria was a city that existed before Nightfall in the present-day location of DisCity. It was destroyed by the impact of the Perishing Star. Little is known about Maria in the present day. It is possible that the city still exists in some form, perhaps as the Underground City.
After years trapped within BR-000 the Keylan expedition was able to reach the ruins of Maria and discover the Source at the city's edge. Although Hestia relates that they were initially ecstatic to escape the temporal maze of BR-000 and begin studying the area, she foresaw that the entire party would be doomed by their discovery of the Source.
Maria is populated by humanoid specters. One specter relive a desperate search for something, which they say is "at the bottom" and for which they "can't stop diving" even if they will "no longer be what [they] were". Another specter asks an unknown entity "about the meaning of your language" and "What you saw beyond the boundary", and believes that the entity "returned to this side... [to give] the prophecy and revelation". A third specter laments that calculations done with data collected while diving makes no sense, and fears that everything they've done has been a waste. A fourth shadow argues with a "great scholar" and claims that they can't "understand the idea of power... [or] humanity" and never trusted it despite coming far together. At one point the shadows seem to conjure a blue light, but a red light immediately shatters it. It is unclear whether these specters were members of the Keylan expedition or inhabitants of Maria who died after Nightfall.