Pleroma is a base of the U-TIC Organization, located on a series of asteroids. In Episode I, Margulis uses Pleroma as a prison for the 100 Series Observational Realian, MOMO. An Ormus cathedral is located in the center the asteroid, which is briefly shown in the game. Pleroma is rendered obsolete when Ziggurat 8 manages to infiltrate it and escape with MOMO. With the secrecy of the base compromised by the Galaxy Federation, it is abandoned in Episode II and destroyed by Sellers and Heinlein. Pleroma is also mentioned by Sellers as having been the name of the original immigration ship from Earth.

In Gnostic lore, Pleroma refers to a 'divine light' that exists above (non-spatial) the physical realm, occupied by spiritual beings self-eminating from the pleroma--called the "aeons" (Greek ὁ αἰών, 'forever') or "archeons" (Greek ἄρχων, 'ruler'). Yeshua is an intermediary aeon from the Pleroma who can help humanity recover the knowledge of its divine origins, bringing humanity back into unity with Pleroma. Yeshua's counterpart, Sophia, separated from the Pleroma to form the demiurge, giving birth to the physical realm.