Gavan is the son of Tamiko Ichijoji and Voicer. Gavan is his real name, but he usually uses his mother's surname as the Earth's name, Retsu Ichijoji. He works at Avalon Riding Club. His outfit is a light brown Double Riders jacket[note 1] and a golden chain on its left shoulder.

As soon as the incident involving Space Crime Organization Makuu occurred, he left the job of the riding club and headed for the investigation, so it was thought that he would "skip the job immediately", and he received only 3000 yen per month. He also does not have the habit of carrying cash because he has lived on Earth for a short period of time, and often borrows a large amount of money when he needs.

He usually stopped by a sports club and was very popular among the children there. He will also spend time playing football with them if he is not busy. However, once Makuu appears, he is a justice man who bravely confronts them. He was driving a red Suzuki Jimny.

At the end of the series, he was promoted to captain.