Ritsuko Amano, biological mother of Nagi Umino and adoptive mother of Erika Amano due to a hospital mix-up at birth, navigates dual maternal roles while balancing her career as a television producer and marriage to Souichirou Amano, a hotel tycoon. Her name, derived from characters signifying "rhythm, law, regulation" and "child," mirrors her methodical approach to both her professional duties and intricate family dynamics. Upon uncovering the infant swap, Ritsuko collaborated with the other parents to orchestrate a marriage pact between Nagi and Erika, intending to preserve familial ties without uprooting the children from their respective upbringing environments. Though met with initial resistance from the pair, the arrangement led her to strategically place them in a shared residence, fostering proximity to nurture their reluctant bond. Her narrative presence revolves around mediating this transitional phase, leveraging logistical decisions to address emotional fallout from the revelation. Details about her personal history or broader evolution remain unexplored in existing material.