Ark seems to be Terra's equivalent to Gaia's Alexander, their elements mirroring each other: Ark is Shadow-elemental, Alexander Holy-elemental; both are mechanical in nature, being feared as ancient weapons and summons, with Alexander being an immobile megalithic fortress, while Ark takes a form similar to an airship; they share the theme of Heaven and Earth, Ark being airborne and Alexander being earthbound; both represent their respective worlds of origin and their names relate to a theme of judgment and punishment, with Alexander known for his attack, Divine Judgment, while Ark's original attack name in Japanese was Dark Fate.