"Dolls are far more intriguing than people. You never grow sick of them."
Yukito Ayatsuji (綾辻 行人, Ayatsuji Yukito?) is a detective and one of the main characters in the spin-off novel. He is currently one of the top-ranked person on the Japanese government's list of dangerous ability users.
Ayatsuji has a short wavy blonde hair and gold eyes. He wears a half-rimmed, light-colored sunglasses, and a black hat. He also wears a jacket with a yellow ochre base with a red collar, a white shirt with a vermillion-based checkered border and a gray knit vest, dull orange checkered knickerbocker pants, and beige boots.
In his hand, he carries a smoking pipe and a doll.
Ayatsuji appears as a cold and emotionless man, though is considered to be fairly odd, as he has a basement full of dolls. He also seems to have a kind side to those he forgives, such as keeping a cat and loving it. He's not very talkative, and often plays with Tsujimura and makes fun of her.
Ayatsuji is also very intelligent (as expected of a detective), and he may or not be just on the same level as Ranpo.
But Ayatsuji is a very dangerous man, dangerous enough to be seen as a threat by the government and to be put on the list of Extremely Dangerous Ability Users.
|Manga Debut:||Gaiden Chapter 1.2|
A plan called 'Exterminate Extremely Dangerous Ability User, Ayatsuji Yukito’ gets submitted to the higher-ups in the Special Division 2-3 times a week but continues to get rejected due to the usefulness of his ability.
- He prefers his coffee with two spoons of brown sugar and no milk. 
- He owns two cats- a black cat and a calico cat.
- Dolls are another of his hobbies, and he not only collects them but also makes them himself in his basement. 
- The hat he is wearing is the same hat as the real-life Ayatsuji is often seen wearing.
- Bungo Stray Dogs Gaiden Manga: Gaiden Chapter 2.3.
- Bungo Stray Dogs Gaiden Manga: Volume 1.
- Bungo Stray Dogs Gaiden: Ayatsuji Yukito VS. Kyōgoku Natsuhiko.