|Birthday||22 January (Aquarius)|
|Likes||Being within his futon, hot springs, yōkan , black-haired Nadeshiko|
|Dislikes||Socialising, twisted things|
|Affiliation||Armed Detective Agency|
|Manga Debut||Chapter 41|
|Anime Debut||Episode 30|
|Japanese Voice||Kenichi Suzumura|
Katai is a dark-haired man who appears to be in his 20s. He wears small circular glasses and is often found resting in his futon within the comfort of his home. When standing next to Natsume Soseki, he is shown to be around average height. His attire consists of a white button-up shirt, a patterned robe over his shoulders, and dark pants.
He is an anxious, nervous, easily stressed out and unmotivated man, who lies in his futon all day, refusing to go outside or communicate with others. Because of this, Kunikida described him as a 'hikikomori' - a term which refers to a recluse who shuts himself at home for extended periods of time, isolating himself from society.
His ability, Futon (蒲団 (Futon?), allows him to control any electronics within sight as long as he isn’t touching them. His ability also enables him to process information dozens of times faster than an average human.
Additionally, it seems that Katai can only concentrate at wherever his body and mind are most relaxed. Although Kunikida mentioned that he can only activate his ability when he’s wrapped in his futon, Katai has shown to be able to use his ability and change the signal of a pedestrian traffic light even without it.
Katai and Kunikida first met each other 10 years ago. According to Kunikida, when Katai was dragged out of his room to join the Agency, he laid out a futon in his office and began living there and even locked himself in his room to avoid going out.
Kunikida and Atsushi paid a visit to Katai to obtain valuable information regarding the hacking of the Moby Dick's navigation controls during the Armed Detective Agency's climatic battle with The Guild.
Katai is supposedly a remarkable hacker that served as an informant for them. However, he is unable to help the Agency right away due to the fact that he is suffering from love-sickness. Katai had fallen in love with a black haired maiden and contracted the Agency to help him confess to her as per Atsushi's suggestion.
It is revealed the woman is Gin, and he is consequently turned down. He is saddened by this, but claims that it is enough for him. Putting the episode behind him, he decides to assist in the investigations.
Some time later, Atsushi went to Katai's house to seek his assistance, but discovered that the scene and his futon are empty. He realised something is amiss, noting that Katai is known to never leave his futon. Kunikida arrives and punches his way through a fake wall to reveal a hidden electronic CCTV recorder that Katai has installed to monitor his room at all times. In the recording, Katai is seen researching the Rats in the House of the Dead, when Fyodor Dostoyevsky suddenly comes up behind him and shoots him. Katai leaves behind a hint of evidence to tell Kunikida that he is safe. He later shows up with Natsume, who reveals that Katai has discovered the base of the Rats.
- His friendship with Kunikida mirrors the real Katai's friendship with Kunikida, after joining the Literary World (文学界, Bungakukai) group.
- ↑ Bungou Stray Dogs Manga - Chapter 50
- ↑ 2.0 2.1 Bungo Stray Dogs manga, chapter 41
- ↑ Bungo Stray Dogs manga, chapter 48.5
- ↑ Bungo Stray Dogs manga, chapter 49
- ↑ Bungo Stray Dogs manga, chapter 50