Niino Hidaka is a central character in the romantic comedy series Marika's Love Meter Malfunction. Presented as a beautiful girl with silver-white hair and blue eyes, Niino transfers to the protagonist Kanata Kitami's school after having moved to Japan from Italy. From her first appearance, Niino stands apart from the other female characters because her love meter, the magical indicator that allows Kanata to see a girl's romantic interest in him, never appears at all. While the love meters of Marika Chitose, Sayuki Toyotomi, and Kokona Mikasa are all visible and fluctuate throughout the story, Niino's remains completely hidden, shrouding her in an air of mystery and making her intentions impossible for Kanata to read through his power. Her outward demeanor is elegant, composed, and refined, matching the polished image of a transfer student with overseas experience. Beneath this graceful surface, however, lies a significant twist: Niino Hidaka is in reality Kanata's childhood friend who has been cross-dressing as a girl. This background reveals that Niino is not actually a female transfer student but a boy who has adopted a female identity, which explains why the love meter power could not register him in the same way it does the other girls. As a childhood friend, Niino shares a deep personal history with Kanata that predates the main events of the series, giving their relationship a foundation of familiarity that contrasts with the newer connections Kanata forms with the other love interests. Niino's role in the story is that of a love rival and a wild card whose presence disrupts the established romantic dynamics. Because Niino is neither a straightforward romantic candidate nor a simple antagonist, the character introduces an element of unpredictability into Kanata's already chaotic love life. The inability to read Niino's feelings forces Kanata to rely on direct human interaction rather than his supernatural crutch, pushing him to grow in his understanding of relationships. Niino's development centers on the gradual revelation of the true identity and the emotional fallout that follows. As the series progresses, the mystery around Niino deepens until the end of episode 7, when a love meter suddenly materializes for the first time. This event sends the story into chaos and transforms Niino from a passive enigmatic figure into an active participant in the romantic and comedic conflict, with the situation escalating into what is described as a superpower battle among the love rivals. Niino's notable ability within the narrative is the immunity to Kanata's love meter power for the majority of the story, which makes Niino the only character whose true feelings remain completely opaque. This unique status gives Niino a strategic advantage in the romantic competition and makes the character a focal point of mystery and dramatic tension. The eventual appearance of the love meter marks a turning point not just for Niino but for the entire story, as the rules of Kanata's power are shown to be more flexible and unpredictable than initially understood.