Description
Riku Nanase serves as the center of the idol group IDOLiSH7. He possesses striking red hair and red eyes, standing 173 centimeters tall. Born on July 9 with type O blood, he loves singing, hot milk sweetened with honey, and heroic stories. He avoids kitchen duties and dislikes the smell of hospitals. His nature is honest, energetic, hardworking, and soft-hearted, frequently accepting requests without hesitation. However, his tendency to speak without thinking sometimes leads to unintentional rudeness or insensitivity. Clumsiness marks his daily life, often resulting in broken objects.

Born with a respiratory illness later identified as asthma, Riku faced repeated childhood hospitalizations. This isolation limited peer interaction, fostering a bookish nature yet leaving him naive about the world. His parents ran a club, making his identical twin brother, Tenn Nanase, his primary caretaker. Tenn often performed to cheer him during hospital stays. At age 13, financial strain from the family's bankrupt club and Riku's medical bills led Tenn to leave home with Takamasa Kujo, resulting in Tenn's removal from the family registry. Riku initially remained unaware of Tenn's true motivations.

Riku joined IDOLiSH7 after Otoharu Takanashi, impressed by his singing during a karaoke outing, scouted him. Though initially suspicious, Otoharu's offer was genuine. Riku's core motivation was to understand Tenn's perspective as an idol and the "view" Tenn sought. Health challenges persisted into his idol career; he frequently concealed or overestimated his physical limits to avoid worrying others, risking serious consequences. Childhood chocolate restrictions due to his respiratory condition were circumvented only by secret sharing with Tenn, causing emotional pain. As an idol, he exhibits low alcohol tolerance, becoming intoxicated even from non-alcoholic drinks like chanmery.

His relationships reflect his earnestness. He trusts Iori Izumi deeply despite frequent arguments, believing in Iori's promise to make him a superstar. His dynamic with Tenn evolved from viewing him as an inspiration to a rival, though their intrinsic bond remains. He shares warm moments with group members, like watching TRIGGER DVDs with Sogo Osaka—often pausing to replay Tenn's scenes—or singing casually with Iori. His emotional expressiveness profoundly impacts audiences, such as crying onstage. This innate influence, termed "monstrous" by Takamasa Kujo, makes him effective in advertising.

Notable habits include hugging his knees when seated and avoiding personal contact exchanges by sharing office numbers. His development shows growing self-awareness in health management and emotional maturity, yet his core optimism endures. He remains driven by a desire to spread smiles worldwide and comprehend his brother's choices.