Aoi Futaba is a teenage girl who once served as a top agent for Japan’s Immigration Bureau, codenamed Momiji, until she defied orders to assassinate the Catian alien Eris and her human ally Kio Kakazu. Declared a traitor, she fled to the Catian Embassy under diplomatic protection. Abandoned as a child due to her innate teleportation ability called Aport, which allows her to summon objects within fifty meters directly into her hands, she survived on the fringes of society. Her family history includes a missing father who was kidnapped and later remarried a Garblian alien, a deceased mother, a Garblian stepmother, and a half‑sister who, due to the Urashima effect of subspace travel, is physically and mentally older than Aoi. Armed with a Dogisian‑engineered battlesuit and a modified blue Ford Shelby GT500 KR equipped with smokescreens and capture nets, she now guards the embassy. Aoi is sixteen years old, 163 centimeters tall, and weighs 40 kilograms, with measurements of 70‑45‑60, black hair, green eyes, and blood type AB. Soft‑spoken and notably shy, she harbors deep romantic feelings for Kio, the only person who treated her normally despite her powers, and she struggles with insecurity about whether he could reciprocate. She frequently seeks advice from her friend Manami Kinjō, and her growing closeness to Kio is marked by shifting from calling him Kakazu‑kun to Kio‑kun. Outside combat, she bonds with Kio over a passion for obscure films. Her journey leads to a polyamorous resolution influenced by Catian custom, culminating in a shared kiss with Kio alongside Eris and Manami.