It is later revealed inside the True Moon that the Maenad is not a singular entity. There are many Maenads brought into being by the true antagonist of "The After Years": The Creator. These beings were born to retrieve the Crystals for their father. It is implied that they also receive their summoning abilities from him, as their powers are not how a summoner's powers usually work: the Maenads overwrite the Code of the Eidolons by trapping them in another dimension and forcing them to serve their will, and by extension, The Creator's.