|Name in Japanese||永澄の父|
|Rōmaji Translation||Nagasumi no Chichi|
|Debut (Anime)||Episode 01|
|Voice Actor (Japanese)||Atsushi Imaruoka|
|Voice Actor (English)||Andy Mullins|
Nagasumi's father is a tall, muscular man with short black hair which is similar to Nagasumi's, and has black eyes. He is often seen wearing a solid tan green short with short pants and slippers, also throughout the series he is seen wearing his glasses.
Nagasumi's father is overprotective of Nagasumi and has a deep hatred towards Sun Seto. It takes little to provoke him and it takes even less to send him on a blind rage, especially when it comes to his son whom he dotes on lovingly. However their are instances where his love for his son take rather unpredictable and insane turns. Nagasumi marrying Sun is, as he sees it, trying to steal him away from him.