Haruko Saeki is a member of the Hoshimi Production group Sunny Peace. She is a student at Seiyou Private University. Haruko is a natural and generous older sister who always has a smile on her face. She is always attentive to those around her, supporting her friends from the shadows and brightening the atmosphere of the place. She made her solo debut a few years ago, but she is a hard worker who has not yet made her mark. She thinks she doesn't have any talent as an idol, but she keeps pushing.