Rika Tokino, younger sister to Kazuto Tokino, aids in running their family's Tokino Bath House. She serves as the pragmatic "straight man," responding with skepticism to the bathhouse’s constant chaos and unusual incidents. Financially driven, she nearly traded Valkyrie for counterfeit cash when offered payment. Academically ambitious, she diligently studies to secure admission to a prestigious college.

Her dynamic with Kazuto blends familial concern over his stubborn commitment to the struggling bathhouse with admiration for his dedication, leading her to support his endeavors. Among Valhalla's residents, she tolerates Valkyrie despite irritations, expresses protective concern for Chorus after her abrupt arrival, and handles Laine’s disruptions with patience. She addresses Mehm as "auntie," viewing Valkyrie and Kazuto’s union—endorsed by Mehm—as a potential financial lifeline. Rika forms a friendship with Sanada after navigating initial confusion about her motives and adapting to her quirks.

On Earth, she maintains a close friendship with Akina Nanamura, though she occasionally questions Akina’s anxieties about her appearance and unspoken affection for Kazuto. In the "UFO Princess Valkyrie: SPECIAL" OVA, Rika participates in the Queen of Valhalla’s "bride training boot camp," paired with Princess Laine for a poverty-management scenario using randomized challenge cards.

Throughout the series and supplementary media, Rika remains consistently pragmatic and studious. Her financial preoccupations and academic goals persist unchanged, while interactions with both human and Valhallan characters cement her role as the narrative’s stabilizing anchor.