Unnamed Parents (Deceased)
Rabbits, Tofu, Hydrangeas, Ghosts
Dogs, Thunder, Flies
Kyouka is a girl short in stature, with dark blue/black hair tied into two low twintails with flower pins.
A notable trait of her (much like almost every member of the Mafia), is that before, her eyes used to be entirely black. But after meeting Atsushi and being together with the Company, those blue eyes have been shown to become clearer.
She always dons a red Kimono with pattern of what looks like sprouts, and its yellow Datejime neatly tied. She wears long white socks and sandals; while on her arms, she appears to wear yellow and red wrist pads.
Kyouka carries with herself a tiny rabbit doll, together with her cellphone in a necklace.
While with the Port Mafia, Kyouka Izumi's personality is similar to that of a doll. She lacks all emotions and is ruthless when she is ordered to perform a duty. After being exposed to Atsushi and the real world, Izumi reverts back to a young teenager. She is easily infatuated with the small things and has a need to see everything.
Much like Atsushi, she believed that she was worth very little and that she deserved to die for her crimes. Although unlike Atsushi, once she joins the Armed Detective Company she does not dwell on her mistakes. She is strong willed and even states that she wants to prove to Akutagawa that she is more than just a killer.
Kyouka seems to care greatly for Atsushi. She shares a room with him and gets worried when he could be in danger. She is by Atsushi's side most of the time.
Kyouka's ability, Demon Snow (夜叉白雪, Yasha Shirayuki?), allows her to materialize a sword-wielding phantom, known as Demon Snow, which only follows orders coming from a mobile phone she always carries on her person. It appears that it only listens to orders from another person on the other line and does not comply to Kyouka's own wishes. Though after joining the Armed Detective Company this problem was fixed by Fukuzawa Yukichi which enables her to control her own ability and use it normally.
In reality Kyouka is not the original wielder of Demon Snow, but instead her mother was. In order to protect Kyouka, in her last moments Kyouka's mother transferred her ability Demon Snow to Kyouka -- but because of the suddenness at the time, control of the demon was transferred to Kyouka's cell phone instead of Kyouka herself.
It is revealed in Chapter 43 that Kyouka's parents had a much darker background than previously thought. Her father, after resigning from being a government agent, become a freelancer who worked for the assassinations of several important people. Her mother was, like her, an assassin who wielded the slaughtering ability Demon Snow.
One night, while Kyouka was out playing, several assassins came to try and kill both her mother and father. While all the assassins were quickly killed by the pair, an unknown ability user who could use body manipulation through blood took control of first Kyouka's father and used him to try and kill the young Kyouka. While Kyouka's mother had cut him down with Demon Snow before he could harm Kyouka, soon her mother was put under manipulation as well. Before her death, Kyouka's mother transferred her ability Demon Snow to Kyouka in order to protect her, using a technique she had learned from an ability user who could manipulate shadows. However, due to the suddenness of the attack, the transfer of the ability was not perfect and so Kyouka's cell phone, given to her by her mother days before her death, became an intermediary for control of the ability.
Since then, the Port Mafia took her, and she served under Kouyou Ozaki as her protegee.
Kyouka first appeared at episode 5, where it appears that she was waiting for someone. Soon after, she approached the person she found, who turned out to be Dazai and kidnapped him using her ability. Afterwards, when Atsushi was out shopping with Yosano, they passed by each other although not giving more than a glance before continuing on their way. Later on, on the train attacked by Motojirou Kajii, she encountered Atsushi again but this time, attacked him on the orders to protect the bomb that was set to go off and blow up the entire train.
After injuring Atsushi severely, she was overpowered and under pressure, revealed that the bomb was on her person, set to go off if any attempt in disarming or removing the bomb was made. Despite this, she provided him with the remote detonator that supposedly allowed the defusal of the bomb but instead it set the timer on the bomb to detonate in a few seconds. Having a change of heart at the end, she decided to jump off the train and sacrifice herself in order to not cause any more damage. Atsushi then saved her by forcefully ripping the bomb off her body and protected her from the blast while falling into the river below. He then brought her back to the agency where she later recovered.
Furthermore, after Atsushi saved her life and the Agency didn't know what to do with Kyouka, Atsushi decided to ask Kyouka out on a "date" to spend some time, to which she agreed. In episode 11, Kyouka was fully accepted and recognized as a part of the Agency by Yukichi Fukuzawa after telling him and to everyone her main goal, to prove Ryunosuke Akutagawa wrong.
In the last episode of season 1 she was also assigned to be Atsushi's roommate and go under full care from him.
- The real life Kyouka Izumi was male, whose real name was Kyoutarou Izumi (泉 鏡太郎).
- In reality, Kyouka Izumi was the protege of Kouyou Ozaki and admired the latter throughout his entire life, pursuing a career in literature due to Kouyou.
- She shares the same room as Atsushi, as revealed at the manga.
- She appears to have photographic memory, often remembering people's faces and loads of information at a fast pace, as shown in episode 17 and chapter 43.
- She made an appearance in the mobile game "Kimito Lead Puzzle 18" as a stage boss and a limited time character.
- Her teddy rabbit was won by Atsushi on a claw machine.
- Atsushi might be really important to her.
- Kyouka can cook skillfully, as shown in Bungo Stray Dogs Wan.
- Kyouka dislikes going toilet at night because she can be killed.
- She likes bunny rabbits and tofu, and dislikes dogs and lightning.
- After being taken in by the Port Mafia, Kyouka has killed 35 people in six months.