Senai plays the role as Yume's stepmother but has raised him as her own son. She, herself, is barren and has never been able to have a child but one day, a woman that her cheating husband had gotten pregnant dumped a four-year-old boy (Yume) on them. At first she despised the child but shortly grew to love him and raise him with little emotional support from Tatsuya, who is always away on business. She is aware of her husband's cheating ways but keeps the marriage together for the financial convenience and the fact that she has had no legal rights to Yume and fears (especially when he was younger) that he would take the boy away from her. She is a very delicate, feminine woman that is generally very graceful in her mannerisms. She appears more than Yume's father and is very important to Yume.