Ajin Wiki
Izumi Shimomura
Yōko Tainaka
Name Izumi Shimomura
Yōko Tainaka
Kanji 下村 泉
田井中 陽子
Rōmaji Shimomura Izumi
Tainaka Yōko
Status Alive
Age 18
Gender Female
Hair Color Black
Eye Color Grey (Manga)
Red (Anime)
Occupations Bodyguard
Student (former)
Height 155cm
Voice Actor Mikako Komatsu (Japanese)
Cristina Vee (English)
First Appearance Chapter 1 (Manga)
Ajin Part 1: Shōdō (Film)
Episode 1 (TV Anime)
Image Gallery

Izumi Shimomura (下村 泉, Shimomura Izumi) is an Ajin. Her name is taken from her birth father's last name (Shimomura) and her mother's maiden name (Izumi).

Her former name was Yōko Tainaka (田井中 陽子, Tainaka Yōko).


A young Shimomura in high school.

Izumi is an attractive young woman with short, black shoulder length hair that appears rather spiky at the start of the series and large, grey eyes (dark red in the anime) with long, prominent eyelashes. There is a small mole under her left eye. Her usual attire is a black suit with a white buttoned shirt underneath, black pants and shoes. When she attended high school, she wore a standard uniform with a tie, skirt, blazer and a white shirt.

At one point in the series, she wore a pink short-sleeved flannel shirt with jeans as her casual wear, saying that "She didn't have anything else."


Izumi is a rather quiet and reserved individual. She talks mainly when informing Yū Tosaki about something. Her answers are usually short and to the point. Even though she is an Ajin, she chose to live with humans in secret and doesn't seem to be consumed completely by resentment towards humans despite her background. She seems to be quite intelligent and understanding, for example towards Tosaki and when interrogating Kei Nagai's younger sister, Eriko Nagai. However, despite her initial stoic appearance, she can get embarrassed easily (for example when she said too much to Eriko and when Tosaki commented on her casual clothes).

Due to her past trauma caused by both of her parents and love life, she became very depressed and suicidal, often cutting herself and eventually trying to commit suicide.


Izumi's former name was Yōko Tainaka and she lived with her mother, Sawako Tainaka, and step-father, Satoshi Tainaka. Her family were poor, a major factor was that her step-father would take Yōko's or her mother's money and spend it on drinking or girls.

When she was in high school, she was in a relationship with Kazuki. She eventually found out that Kazuki cheated on her with another girl as she overheard them talking about her while they're alone. After hearing this, Yōko goes to her home's bathroom to commit suicide by slitting her right wrist with a scissor while her stepfather is in the house. Her drunk stepfather sees her in the bathroom and attempts to rape her.

Yōko stabs him with the scissors while he slams her head into the side of the sink, killing her. While this happened, her mother returns home to see Yōko dead, Yoko begins to ooze out IBM and comes back to life after being dead, thus alerting her family that she's an Ajin. Her step-father calls the government to try to sell Yoko to them, but her mother wholeheartedly disagrees causing a fight in which they stab each other and die. Yōko left the house before the fight between her parents started, and so she was unaware of their deaths until Tosaki informed her. She eventually wanders in the street and it's implied that she becomes a prostitute to survive in the streets. During this period, Izumi becomes aware of her black ghost.

She eventually collapses from a sexually transmitted disease and is visited in the hospital about 2 weeks after the Shinya Nakamura incident by Yū Tosaki as Tosaki had a gut feeling that she might be an Ajin due to the earlier call to the police by her stepfather about her being an Ajin. Tosaki talks to her and plays the phone call of her mother and step-father's fight in which both of her parents killed each other. Upon learning the true events of what happened, she asks why he'd play that it's too late already. Tosaki replied that he's just correcting her view of her parents because her mom did, in fact, love her, to which she seemed nonchalant.

Just as Tosaki is about to leave the room since he deems that she's actually not an Ajin, she succumbs to her disease but is brought back to life, shocking Tosaki who was present in the room and confirming his suspicion. Afterwards, she gets a special contract with Tosaki in the condition that "Yōko Tainaka" is dead and she will live on a new name while she becomes his escort. She decides her new name to be Izumi Shimomura, taken from her mother's maiden name and her birth father's last name.


Sawako Tainaka[]

Izumi cared for her mother and did not understand why she was with Satoshi. She hated her after thinking she wanted to sell her to the government. After learning the truth, she cared for her again and promised she won't run after getting her new life as Izumi Shimomura.

Satoshi Tainaka[]

Izumi had a strong dislike for her step-father, as he kept them poor. She hated him after he attempted to rape her, killed her, and tried to sell her to the government.

Yū Tosaki[]

She is Tosaki's personal bodyguard. He relies on her heavily, however, he does not hesitate to threaten her if she fails to do her job correctly. Even though it was shown that Izumi seems to understand Tosaki, she is still quite anxious in case of making a mistake in front of him, such as the time where she accidentally asked Kei's sister if her brother has seen as Black Ghost, later saying that she was glad that Tosaki wasn't there at the time. We discover that the reason that Tosaki still keeps Izumi's status as an Ajin a secret is because he considers her as a valuable escort in case anything might happen to him.

When they were attacked by Sato, he revealed to her that her status is kept in a bank vault and the keys to the vault is in the safe beside Tosaki's fiance's hospital bed. Tosaki voided their contract and told Shimomura to run away from Sato. Instead, she decided to stay and protect Tosaki, saying that she is free to do that since the contract is voided. She also thanked Tosaki for giving her a new life. Tosaki and Izumi's relationship is professional only.

Abilities and Powers[]

  • Immortality - Similar to all Ajins, Izumi is immortal.
  • Invisible Black Matter - Izumi also possesses IBM and can manifest her Black Ghost which she calls Kuro (which translates to Black.) Her Black Ghost's unique physical trait is its head shaped like an elongated pyramid. It is shown that she can control her Ghost properly as she can command it to protect Tosaki and fight other Ghosts.
  • Paralysis Scream - It is assumed that Izumi can also use a Paralysis Scream since she's an Ajin but this has never been demonstrated in the series yet.


  • Izumi's personality is similiar Rin Shimotsuki from HinaBitter♪ song series by Konami, with both of them being calm and composed. Interestingly, Rin also has beauty mark on her left eye like Izumi.
  • Izumi's real name and her assumed last name ("Yoko" and "Shimomura", respectively) is a direct reference to legendary video game composer Yoko Shimomura, who created the soundtracks for such games as "Legend of Mana", "Super Mario RPG", the entire "Kingdom Hearts" series, and most recently "Final Fantasy XV". This may be due to Sakurai Gamon's love for video games.
  • The appearance of Izumi's IBM is very reminescent of Pyramid Head from the Silent Hill series with and a elongated pyramid on it's head and a muscular body.

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