Chitoge and Seishiro share a very special relationship backed up by their respective childhoods. Aside from Raku, Seishiro was once a frequent playmate and friend to Chitoge. Seishiro greatly treasures her time with Chitoge, owing to her her happiness and all the precious memories of her despite being unaware of her own true origins; Chitoge was the one who gave Seishiro the date of her birthday - the day they first met - and also provided Seishiro her signature light-blue ribbon. Because of this, Seishiro developed strong feelings of love and dedication to Chitoge, pledging to become strong enough to protect her. Hence, Seishiro trained herself and rose to become one of Beehive's most effective agents.