Lilly Bell attends Hakuoh Academy and actively serves in its Space Yacht Club, operating communication systems on the club's yacht, the Odette II, with notable proficiency. Her technical expertise extends to systems aboard the pirate vessel Bentenmaru, showcasing versatility in spacecraft operations gained through dinghy simulation training and hands-on experience with various technical setups.

She possesses light gray hair and purple eyes, often depicted wearing headphones during operations. Her personality blends an affable, easy-going demeanor with a playful inclination for pranks—such as stealing underwear during space suit changes or adding capsaicin to curry—typically targeting fellow club members like Maki Harada and Chiaki Kurihara. Despite these antics, she maintains a close friendship with Maki, frequently appearing alongside her.

Born into a wealthy space-trading family, Lilly chose piracy for adventure and excitement while demonstrating familial loyalty through regular financial support sent home. During the Bentenmaru's intervention at the Princess Apricot yacht, she assisted while wearing a medical personnel outfit of white with blue accents.