Yukiko Shirato is the president of Shirato Konzern, the company that once organized the Megalonia tournament that determined the most powerful king of the Megaloboxing world. Today, she is a powerful business partner of Sakuma. Her older brother is Mikio Shirato.
Prior the events of season 2, Yukiko is seen at the funeral where Sachio tells Joe not to come back, and a number of Sachio's friends are given residence at an orphanage she runs before they come of age.