Lime Shijo, also known as Raimu Shijo, serves alongside her twin sister Yuzuki as a Guardian of the Common, an unseen world that collects human emotions. Both sisters perished in a tragic accident but were temporarily resurrected by the Common to recruit Reflectors, including Hinako Shirai, to defend against threats such as the Sephirot and later the Ash Phenomenon. Their initial recruitment of Hinako involved deception, promising her a wish to heal her injured leg in exchange for cooperation, though fulfilling this wish proved impossible. The sisters later revealed their true motives, explaining that victory would reset the timeline and erase Hinako's memories of them, despite their deep care for her.

Lime possesses long wavy blonde hair, pale green eyes, and stands 146 cm tall. She typically wears the Hoshinomiya Girls' School uniform with a blue neck ribbon, white thigh-high stockings, and brown dress shoes. As a Reflector, she dons a ballet-inspired costume: a white and blue leotard, white skirt, green flower barrette, full-length white gloves, calf-length white boots, and a green chest bow. Her primary weapon is Mr. Bear, a magical teddy bear capable of expanding in size and functioning as a puppet.

Logically pragmatic and occasionally stern, Lime prioritizes mission success over individual welfare, manipulating school dynamics to intensify emotions and create stronger Fragments for collection. Despite this utilitarian approach, she displays fierce loyalty to her sister Yuzu and Hinako, reacting protectively when others threaten or criticize them. Her demeanor is generally emotionless and stoic, contrasting with Yuzu's energetic nature, though she participates in school activities and enforces boundaries when time is wasted.

Lime's role evolves significantly across the series. In *Blue Reflection*, she assists Hinako in stabilizing Fragments and battling Sephirot while concealing the truth about her and Yuzu's afterlife status. In *Blue Reflection Ray*, she defends the Common against Mizusaki Shino's incursions. During *Blue Reflection Tie/Second Light*, she and Yuzu create Oasis—a sanctuary island school—to shield Reflectors from the Ash Phenomenon. Lime sacrifices her power to sustain Oasis, falling comatose, while Yuzu loses her emotions. Both are restored by Hoshizaki Ao and other Reflectors, who confront the World System to reset the timeline pre-Ash. In *Blue Reflection Sun*, Lime appears in "The Land where God Lives," guiding the Protagonist to purify the area using Eroded girls' potential. She identifies the Cosmic Fang tower as the world's heart and directs efforts against the Testa.

Her name "Shijō" derives from "officer, boss" (司) and "castle" (城), while "Raimu" means "come" (来) and "dream" (夢).