Tomarin hails from the O-12 Cluster, an extraterrestrial stranded on Earth following her spacecraft’s crash, caused by a leaking fuel tank. She crosses paths with Marimo Bando, becoming her roommate and forging a chaotic friendship fueled by mutual eccentricity and comical miscommunication. Her damaged ship relies on a yellow liquid fuel, which she confuses with canned beer stockpiled in Marimo’s basement.

To convince Marimo of her alien origins, Tomarin displays telekinetic powers and presents her wrecked UFO, though skepticism lingers until she unveils her startling true form—a grotesque physical manifestation. This moment cements their bond, marked by frenetic, absurd exchanges and a shared tendency toward whimsical simplicity.

Though generally cheerful, Tomarin occasionally reveals vulnerability, such as startling easily. Her interactions with Marimo spiral into surreal escapades, including ambushing her in the bathroom or conjuring bizarre phenomena. These antics position her as a trigger for absurdity, intertwining seamlessly with Marimo’s own erratic quirks to amplify their shared unpredictability.