Kyūsaku Yumeno, often referred to as Q, possesses a deeply twisted and sadistic personality that belies their youthful appearance. They take a disturbing delight in the chaos and suffering wrought by their ability, Dogra Magra, reveling in the carnage and despair it creates. Though capable of portraying an innocent and harmless child when it suits them, Q can instantly shift to a more sinister and malevolent demeanor, showcasing their dark nature and manipulative tendencies.

Their dangerous behavior led Osamu Dazai to confine them within the Port Mafia, recognizing the threat their unpredictability posed even to their allies.

Following their abduction by the Guild, Q experiences severe physical and emotional torment. While trapped within John Steinbeck’s ability, which spreads pain throughout Yokohama, Q is forced to endure the agony felt by the trees under its influence. The overwhelming suffering breaks Q’s psyche, pushing them to curse the entire city. This emotional breakdown reveals their inner turmoil, including a deep-seated hatred for humanity, themselves, and their own ability, which they never desired. This moment offers a rare glimpse into the tragic and tormented psyche underlying Q’s sadistic exterior.

Kyūsaku Yumeno, commonly known as Q, has a distinctive and eerie appearance that reflects their unsettling nature. Their hair is strikingly two-toned, with the left side white and the right side black. Their eyes are equally unique, featuring mismatched pupils: the right eye contains a yellow star, while the left has a yellow ring.

Q’s attire is childlike yet odd, contributing to their unsettling presence. They wear a small hat tilted to the left and a white shirt paired with suspenders. Over this, they don a black coat and a scarf around their neck. Beige shorts with thin red stripes, high white socks reaching their calves, and brown shoes complete the outfit. They also carry a red sling bag featuring a design resembling a cat or dog, adding a deceptively innocent touch to their appearance.

Integral to their ability, Dogra Magra, Q always carries a doll, which serves as a vital component of their powers. This doll is often seen in their arms, symbolizing both their childlike guise and the menace they bring.

Kyūsaku Yumeno, commonly referred to as Q, joined the Port Mafia shortly after Osamu Dazai’s own recruitment. Tasked with discovering the nature of Q’s ability, Dogra Magra, Dazai quickly realized the danger and volatility posed by the child. It is suggested that Ōgai Mori, the leader of the Port Mafia, kept a close watch over Q, likely understanding the destructive potential of their power.

At some point, an unspecified incident occurred, resulting in significant casualties within the Port Mafia. This catastrophe, presumably caused by Q’s ability, prompted Dazai to take drastic action. Recognizing the risks of allowing Q’s abilities to remain unchecked, Dazai personally saw to it that the child was confined, neutralizing the threat they posed to both the Port Mafia and the broader city of Yokohama. This decision underscores the extreme measures the Mafia is willing to take to manage its most dangerous assets.

Kyūsaku Yumeno’s ability, Dogra Magra (ドグラ・マグラ), is a powerful mind-control curse that wreaks havoc on its targets, referred to as “receivers.” When triggered, the curse assaults the consciousness of the receivers with intense hallucinations, driving them into a frenzy where they indiscriminately attack everyone around them—friends, foes, allies, or enemies.

The curse is activated when someone “hurts Q” by making contact with the razor blades taped to their arms, causing injury to Q. Once this happens, Q mutilates their doll, which acts as the source of the ability. This action places a hand-shaped blotch on the receiver’s body, marking them as cursed. The doll, despite being mutilated, has a self-regenerating property, allowing Q to use it repeatedly for their ability.

The devastating effects of Dogra Magra make it an immensely dangerous and volatile power. To date, the only known method of neutralizing the curse is through Osamu Dazai’s ability, No Longer Human, which nullifies all abilities upon contact. This makes Dazai one of the few individuals capable of effectively countering Q’s destructive potential.

Yumeno’s unique ability makes them an invaluable, albeit dangerous, member of the Port Mafia. Their presence often serves as a last resort for the organization, as their ability’s destructive nature can harm both enemies and allies.

Yumeno’s actions frequently destabilize situations, sowing chaos and fear. Their sadistic tendencies and lack of moral restraint make them a symbol of the Port Mafia’s darker and more uncontrollable side.

Yumeno is considered a threat not only to the Armed Detective Agency but also to their own allies within the Port Mafia. Their unpredictable nature and disregard for authority make them difficult to control, often causing collateral damage that further highlights their chaotic role.

Kyūsaku Yumeno serves as a symbol of chaos and unpredictability in Bungo Stray Dogs. Their ability, Dogra Magra, and their erratic behavior underscore the darker aspects of the Port Mafia, showcasing the organization’s willingness to embrace even the most unstable individuals for the sake of power. Yumeno’s unsettling presence and psychological manipulation make them one of the series’ most haunting and memorable characters.