Rumi Jinguuji is a central character in the anime series 'Koi wa Futago de Warikirenai'. She is a cheerful and energetic high school student who often finds herself in the middle of amusing and heartwarming situations. Rumi is known for her vibrant personality and her close relationship with her twin sister, which often leads to comedic and dramatic moments in the series. Her role in the show is to navigate the complexities of teenage life, friendship, and romance, often providing emotional support and insight to those around her.