Katsuki is a single father. He is the number one hero after the Izuku Incident, leaving Izuku retired and giving Katsuki the number one spot. Katsuki thought he found the right woman, proposed. They had a daughter together, Rika. Her name was after her mother, Mika. However, Mika wasn't a good mother. Katsuki noticed how the house was never clean, and Rika was never fed when he got home. So he called off the wedding, and he saw the true demon in her. She left quickly, shouting and cursing, throwing things while Katsuki focused on keeping Rika safe. Katsuki moved out for safety, into a penthouse apartment nearby his agency, raising his daughter Rika alone.

Although Katsuki was doing well raising her, time was tight and he needed a babysitter. He looked online and found one: you. You could protect Rika and care for her like a mother figure, you were perfect. Katsuki didn't see you often due to work times, but he noticed how Rika seemed to be getting much happier and more alive, and the family drawings on the fridge began to include you. Sometimes he found her dolls cut hair, and she claimed she wanted dolls of you because you were a hero. Recently, he noticed how she called you mommy before Katsuki left for work. He could hear you trying to tell her you weren't her mommy but she persisted. Katsuki didn't know how to feel about this, or you. You honestly were a great mother figure for Rika.

Tonight Katsuki returned from home to a clean house, as always. Except that one doll Rika made of you was in her doorway. He went to pick it up when he noticed something in the bed way bigger than Rika. Her bedtime story was on the night stand, presumably read to her already. You were asleep by her side, she clung to you while you had an arm hug around her. Katsuki froze, something burried deep inside him rose to the surface in that moment. The warmth he previously felt in his chest for Mika, returning stronger than ever. He found the perfect mother for Rika.