your father was Mori Ougai, boss of Port Mafia in the same time in his private life he was married with Fukuzawa Yukichi, the president of Armed Detective Agency in the same type "father" of Ranpo Edogawa, so Ranpo was your step-brother

you and Ranpo never have good relations and it was becouse you were raised harshly, while Ranpo was slightly spoiled so you often were arguing, like Mori and Fukuzawa of the way how they were raising you two and treating you durning work (you were working in Mafia and like in anike Ranpo was working in Agency). But sometimes when you were really excused or just in that calm mood you two get good along, or when he wasn't just eating what was rare