Setsuna is a young man with long-ish dyed blue hair and brown eyes.
He dresses in what Itsuki classifies as Shibuya fashion, wearing an orange T-shirt with a circle on it over a black long shirt. He also wears some baggy green pants and black boots.
Setsuna is an easy-going guy who likes hanging out at Itsuki Hashima's apartment. He dropped out of school because he was too lazy to study, and initially wanted to draw manga, but that was also too much work for him, so he decided to become and illustrator and gained a lot of popularity.
Setsuna is awful to work with, since he doesn't own a phone and rarely responds to his emails while drawing. Additionally, he has the habit to go on sudden unannounced trips from time to time, causing his editors much anger (especially Kenjiro Toki, who at one point trapped Setsuna in a room and forced him to finish his work). Even so, people still want to work with him because of his amazing talent.
Setsuna is a genius illustrator that was paired Itsuki Hashima for the authors light novel.
Setsuna is a really talented artist that has a fetish for asses and is in search for a perfectly plump ass (such as Chihiro Hashima's) as inspiration.
Setsuna is shown to look up to his partner Itsuki Hashima.
Itsuki has worked with him on one of his series before, and loved his work. However, Itsuki denied Setsuna the chance to draw for him again, as he feels his novels aren't good enough for a god of illustration like him. One day, when Itsuki creates a novel he is truly proud of, he hopes Setsuna will partner with him again.
Even so, the two often hang out and play games, and Setsuna generally looks up to Itsuki.