This entity was originally a godlike being from an outer plane of the Agnastoria universe (The world Riventla Nuck lives in). When it transdimensionally moved to the Pixiv Robot Wars universe, it took the form of an extremely powerful, 63-meter tall mecha. Seirios (Σείριος, "glowing" or "scorcher") is the name the Earth Alliance Forces call the mecha.
Its alternate universe form is called "Seirios IF". Almost failing to materialize in the human world, it took a form of an extremely weak, pudding-crazed woman. She has longwhite hair and flat chest.
