|This page contains major spoilers. Read at your own Risk!|
146 cm (4'9")
Himself, chaos, brown sugar
Himself, peace, society, hospitals
He wears a mini hat in a diagonal position. He wears a white shirt and suspenders with a black coat with a scarf around his neck, along with shorts with thin red stripes, and brown shoes with high white socks that reach his calves. It is shown that Yumeno carries a sling bag with an animal picture. He is also constantly showing a rather scary smile and he always carries a creepy doll.
Q's hair is divided in half down the middle, with the left half of his hair being white, and the right being black. His eyes also exhibit a rather different design, with his right pupil being a solid yellow star, and his left being a yellow ellipse that is dark blue in the middle, the same color as his irises.
He seems to hate Dazai as he was the one who had sealed Yumeno in the past. He wants Dazai to feel pain and pay but spares him. Yumeno also loves to manipulate his enemies by hurting his comrades by using his ability. As Dazai said, he doesn't discern whether or not a person is an ally or a foe.
His ability, Dogra Magra (ドグラ・マグラ, Dogura Magura?), is a mind control curse that curses his targets or 'receivers' by ravaging their consciousness with hallucinations, causing them to attack everyone in sight with no regard on whom they might be; allies or foes, friends or enemies.  The 'receivers' are those that "hurt Q", by bumping into him and causing the razor blades taped to his arms to cut into him. This curse is triggered by mutilating a doll that he constantly carries, which is the source. A blotch in the shape of a handprint appears on the body of the cursed one when the curse is triggered by the mutilation on his doll.
He was, together with Dazai, under the care of Ougai Mori.
At some point, because of the horrid nature of his ability and his demented state of mind, a decision to seal him up was made. He was eventually successfully sealed, but not without a massive death count.
He first appears when he introduced himself to the two detective agency affiliates on the train. After leaving the train, he deliberately bumped into Atsushi, who was waiting for Naomi and Kirako at the train station. This made Atsushi the target of the curse, and Atsushi then proceeded to unknowingly attack Naomi and Kirako. Atsushi's hallucination was ended by Dazai, who nullified the curse after finding the doll. Yumeno leaves on the train, but not without mocking how weak Dazai's 'new friends' are and swearing that he'll break Dazai himself. Dazai delivers his own threat, saying that next time Yumeno won't just be sealed, but have his heart hollowed out.
A week later, Yumeno is seen walking and looking for some entertainment. He meets Lovecraft and asks him to entertain him. After having seen a bit of Lovecraft's ability, Yumeno uses his own against him but it interrupted by Lovecraft himself, who attacks and kidnaps him. He is later seen tied by roots, suffering and yelling that he would kill and curse those who did this to him. John stays with him and reveals that his sufferings are due to the root being connected to him and all the trees in Yokohama, meaning that all those who harm trees in anyway are the ones who harm Yumeno. He also says that their plan is to use Yumeno to destroy Yokohama- as soon as Yumeno's ability will activate, those who harmed the trees will be cursed. Being desperate, Yumeno claims that all he wanted was to live happily and that he has never asked for the ability he has. At this, John answers that Yumeno couldn't do anything about it and that he wasn't loved by God. Due to the extreme physical and mental pain, Yumeno activated his ability. A while later, after Dazai nullified Yumeno's ability, Chuya and Dazai come to take Yumeno back, who is unconscious.
- Yumeno claims that he has never asked for the ability he has, and that all he wanted was to live happily.
- In the same way that Edgar Allan Poe inspired Ranpo Edogawa in real life, HP Lovecraft inspired Yumeno Kyuusaku in real life.
- Dogra Magra is a novel by Yumeno Kyūsaku (pen name of Japanese author Sugiyama Taidō)
- ↑ Bungo Stray Dogs Chapter 25 page 35-36
- ↑ Bungo Stray Dogs Chapter 25 page 16
- ↑ Bungo Stray Dogs Chapter 25 page 17, 23
- ↑ Bungo Stray Dogs Chapter 22 page 23-24
- ↑ Bingo Stray Dogs Chapter 25 page 36
- ↑ Bungo Stray Dogs Chapter 22 page 12
- ↑ Bungo Stray Dogs Chapter 24 Page 30
- ↑ Bungo Stray Dogs chapter 25 page 13-23, 33
- ↑ Bungo Stray Dogs Chapter 27 page 25-29
- ↑ Bungo Stray Dogs Chapter 27 page 2-4,10-15
- ↑ Bungo Stray Dogs Chapter 31 page 6-11
- ↑ Bungo Stray Dogs Chapter 27 page 12