Race: Human

Age: 14

Powers: Enhanced strength & agility, rapid healing, heightened senses, ayakashi transformation

First Appearance: Manga Chapter 48, Anime Episode 21

Gen first appears with Kyoichi Hiba, as the two are inspecting Karasumori Academy at night. He then shows up at school the next day as a transfer student in Yoshimori's Middle School.

Gen Shishio is the youngest son of the Shishio Family and a member of the Night Troop. He is an Ayakashi Majiri and possesses a wolf-man transformation. Gen is sent to Karasumori by Masamori Sumimura to help Yoshimori and Tokine fight against Kokuboro.

Gen has a very serious appearance for a young teenager, possessing sharp eyes (due to being half Ayakashi) like an animal's, with sharp spiky black hair, and a dark skin tone. His clothing mainly consists of two outfits, the one he wears during battle consists of a ninja like costume with purple pants and a short sleeved robe with arm guards on both his arms and legs. His outfit also carries The Shadow Organization Star symbol. During his stay at Karasumori Academy, his regular clothes mainly consisted of the Middle School's uniform. He also carries a special flame tattoo around his body, given to him as a young boy in order to keep him from fully transforming.

Gen had a very solitary nature, and was slow to trust or even interact with anyone. He had trouble understanding the way other people behave, and spent a great deal of time observing them and reflecting. He was particularly puzzled by the partnership between Yoshimori Sumimura and Tokine Yukimura (since their families are supposedly still feuding), and could not understand what Yoshimori sees in such a "scary girl." Even when around people he considered friends, Gen only opened up so much. Like Yoshimori, Gen thought nothing of stepping in to save someone despite any danger to himself, though his reasons stem from Masamori entrusting him with his duties.