Rika Tokino works alongside her older brother Kazuto running the family's Tokino Bath House. She diligently balances this responsibility with focused academic studies, aiming for admission to a strong high school and university to secure education and financial stability. She often voices worries about the bathhouse's viability as a sustainable business and the family's economic future. This pragmatism sometimes leads to extreme ideas, like her willingness to sell Valkyrie for money when an opportunity arose, though she abandoned the plan upon discovering the cash was counterfeit.

Within the bathhouse, Rika frequently acts as the "straight man," offering grounded reactions to the supernatural chaos involving the Valhallan princesses and their associates. Her relationships vary: she maintains a friendship with Valkyrie despite occasional annoyance, cares for Kazuto while wishing he were more perceptive, and shares a close bond with Akina Nanamura, though questioning Akina's focus on appearance. Her initial wariness towards Sanada softened into friendship despite Sanada's quirks. Among the royalty, she tolerates Princess Laine despite irritation at her frequent crash landings, insists on calling Princess Mehm "auntie" against Mehm's preference for "big sister," and exhibits general concern for Princess Chorus while baffled by her closet residency.

Rika consistently supports the romantic relationship between Valkyrie and Kazuto. Part of her motivation stems from seeing their potential marriage as a way to ease the Tokino family's financial burdens through connection to the Valhallan royal family, highlighting her pragmatic view of economic advancement. Her core traits of fiscal caution and academic dedication remain steady throughout the series, though she develops greater adaptability to the extraordinary bathhouse circumstances. This adaptability is evident during Valkyrie's separation into distinct adult and child forms, where Rika continues her supportive role without significant disruption to her duties or demeanor.