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Isuke Inukai (犬飼 伊介; Inukai Isuke) is one of the main characters of the manga and anime series Akuma no Riddle. She is a former student of the 10th year's Black Class of Myōjō Academy who was in a competition with the other students of that class who all were set to try successfully killing Haru Ichinose where the reward was anything the assassin wishes for. The reward she requested for was enough money for herself and her parents which would be used to build a house for her parents either in the Caribbean or the Alps. 


Isuke has long, pink hair that reaches her lower back. While the rest of her hair is straight, two side bangs framing the sides of her face are curled like ringlets. Her eyes are golden and have long lashes. Her usual attire seen throughout the plot (both manga and anime) consists of a small purple neck scarf, a long sleeved black jacket that shows her midriff, a purple plaid skirt, and a pair of knee-length, high-heeled boots. She has purple nail polish on her nails.



Early in her life, Isuke lived with her brother in a derelict house where her parents locked them in and neglected them. The names of her biological family are unknown. She recounted to Haruki how she and her brother eked out a living in that house, scrounging for scraps like moldy bread among trash and filth. Their parents would come in to occasionally leave them food, but their visits became infrequent. Eventually, her brother dies from the ill living conditions.

Isuke would likely have perished as well, but Eisuke Inukai happened to be nearby and killed them. He introduced himself and gave a new name to her on the spot, claiming that she will be his new daughter. He kisses her hands and tells her about his being an assassin by trade. This day is what she considers her official birthday. Isuke's birth name and original birthday are unknown.

Black Class

Isuke is a bit of a slacker in class. She claims she will not hide her intentions by playing school with the others, and therefore does not apply herself at all in class. She even sleeps in class and gets abysmal grades as a result. Additionally, she encourages antagonistic behavior, like saying bullying is cool when Takechi steals Banba's strap. It is revealed she does miss her family as she is participating in the class. She makes calls to her Mama to give them assurances of her return.

Unofficial Assassination Attempt

She was the very first assassin in the school that tried to kill Haru, going for the kill very close to the first day of class. However, she does this before the secret orientation, thereby acting before the rules are introduced. She pretends to be friendly with Haru to get into her room, promising that she has some special tea. She actually swapped the tea contents with about 3 milligrams of some somniferous, which puts Haru to sleep briefly. Isuke had planned to undress Haru and throw her in the bath to drown her while she was drugged. However, Tokaku arrives, having received a tip from Haruki. Upon being interrupted, there is a brief struggle and Isuke gives up, leaving.

Room 2

Isuke interacted frequently with her roommate, Haruki, before the latter's expulsion.

One of their first interactions was Isuke getting grappled Haruki in surprise as the latter gets a better look at her nails.
Nail Polish
In the drama CD and the manga, Haruki breaks one of Isuke's nail polish bottles and promises to pay her back, though the cost absolutely stuns her. This leads them to discuss money and family, ending with Isuke agreeing that she will do anything for family despite her love for money.
20th Birthday
At some point during her enrollment in class, on June 29th, she turns 20 and celebrates her birthday with Haruki. Isuke gets drunk and dreams about the day she was adopted, but for some reason sees Haruki in the dream[1].
Haruki's Expulsion
Following Haruki's failed assassination attempt on Haru, Isuke goes to see her roommate in the hospital and does her nails for her. She promises she will see her often. Haruki leaves only three days after being severely injured by her failure. As she is packing to go, Isuke gives her a bottle of nail polish, identical to her own. Haruki then kisses Isuke and leaves her stunned. Isuke is slightly angered by the other girl's actions, but she then thinks better of it and says she'll kill Haruki if the price for her lips cannot be paid[2].

Official Assassination Attempt

Later on in the series, she was the seventh person to attempt an attack on Haru after sending out a warning letter. With only 3 other assassins remaining, Haru receives a warning letter with Mahiru's name on it. When Haru and Tokaku reached the front of the dorm building, Isuke was there and suddenly tries to attack Haru with a knife, but Tokaku successfully defended Haru from the attack. They then realized that it was Isuke who sent the warning letter instead of Mahiru. Tokaku fought briefly for a moment with Isuke, but got injured by Isuke's attacks afterwards. Tokaku threw mud at Isuke in order to blind her, then ran away with Haru, bringing Haru to an empty class and locking her in.

Tokaku thought that Haru would be safe away from Isuke and proceeds to jump through the window. She is then confronted by Isuke and fights her again, but they suddenly hear a loud noise coming from the room where Haru was. Isuke reveals that Shinya is punctual, and that they made a promise whereby Shinya would "play" with Haru while Isuke takes care of Tokaku. The two continue to fight when Tokaku's cellphone receives a sudden message from Kaiba. The distracted Tokaku then gets caught in a neck lock by Isuke, and then her cell drops onto the ground and Isuke proceeds to smash it. Tokaku struggles for a few seconds and drops her knife, but she was unable to set herself free. She then activates a hidden taser in her shoe, zapping Isuke on her back, stunning her for a brief moment. Tokaku then proceeds to pick up her weapon to finish off Isuke when suddenly she stops and remembers a shrine. Isuke tries to take advantage of this moment, but wasn't recovered fully, and Tokaku landed a kick to her gut knocking her to the ground. She then runs off to look for Haru. However, not long after, Isuke shows up behind her and the two of them start to fight again. While Tokaku was dodging attacks, she was cornered and leans on a glass window allowing Isuke to push her off the building.

Isuke then heads to the audio visual room where she finds both Haru and Shinya, and she turns on the projector at the top of room which reminded Shinya of her terrible past. Isuke then picks Shinya up by the head and sent her flying with a kick. Isuke's attention then focuses of Haru and begins strangling her as they both thought that Tokaku is dead. However, just in the nick of time Tokaku shows up stopping Isuke by throwing a knife in her wrist. Isuke pulls the knife out of her wrist and tries to shoot Tokaku but the bullet only grazes her and she tries a second time but Tokaku dodges the bullet and hits the gun out of her hand. Tokaku then pins Isuke to the ground using her leg and pulls on Isuke's right arm eventually breaking it. Tokaku gets off of her and sits on top of her, still holding her arm. Tokaku uses her left arm to pin Isuke's head down and then grabs her neck and chokes her until she becomes incapacitated.

Isuke and Banba become the eighth and ninth person to be expelled from the Black Class.

After Black Class

Isuke & Haruki

After the events of Black Class, Isuke is seen on a tropical beach with her family on the phone with Haruki, to whom she is now dating. The two of them are wearing rings. They exchange a bit on the phone and Isuke tells her that Haruki should hurry up to come back home or she'd get angry. Eisuke then jokingly remarked that he's wondering how caring his adopted daughter can be towards her lover to which Isuke simply replies with saying she just loves Haruki and can't help it.

In Koakuma no Riddle, Isuke and Haruki meet up repeatedly after their expulsion, and Isuke even shows Haruki to her parents. On one of their nights together, Isuke questions Haruki would ever move past her, to which Haruki says she would gladly kill people for her.

Isuke later takes Haruki to her biological family's grave. She tells Haruki that she would never forgive her if she died before Isuke did.


She has a sadistic and a somewhat narcissistic personality. Isuke is rather blunt when she speaks, and she likes to express her opinions. Her smile is often saccharine or murderous.

Isuke pistol

Isuke attempts to shoot Tokaku.

She also likes to command other people, such as making Haruki Sagae call her "Isuke-sama". Isuke is also easily annoyed by trivial things, and she doesn't care about school work or helping others. She believes it is the fate of the weak to die, which is why she fights for herself.

What also seem to annoy her is when she's not able to knock a target of hers successfully at first attempt. In such a situation, Isuke even is prone to use a pistol and shoot her target, spilling blood if needed.

She does have a caring side, as shown toward Haruki and her adoptive parents. Kouga Yun characterizes her as a tsundere.


  • Sagae Haruki: Haruki was Isuke's roommate in Room 2 during their enrollment in Black Class. While at first Isuke was annoyed at Haruki and her nonchalance, she eventually shows some care for Haruki and digs a little into her past. She goes as far as to offer her advice on being more selfish. After Haruki's expulsion, it is shown in Koakuma No Riddle that Isuke actually went to go visit her in the hospital and also helped her with her nails. When Haruki packs up to leave the academy, Haruki kisses Isuke, which makes her frustrated. But she seems to reciprocate these feelings.

Skills and Abilities

002 (1)

Isuke drawing her handgun.

Isuke is skilled at hand to hand combat. She has the strength to strangle someone with her scarf. Using her trench knives, she is also able to hold her ground against Tokaku's knife-wielding. She is also proficient in firearms, though she does not really like to use tools which spill blood. Her fingers are mentioned to be dexterous.

In the mental department, she is shown to be cunning. She easily deduces Tokaku's weakness and virgin assassin status in their first tussle. She also plans far enough ahead to trick Haru with a notice that she wrote Banba's name on, as well as collaborating with Banba and then ditching her to kill Haru herself. She also ascertained Banba's weakness to light and was able to use it against her.


  • In the postscript of the first manga volume Yun Kouga states that Isuke has the largest breast size of all female characters in Akuma no Riddle. This is echoed on her profile in the Akuma no Riddle AK game. There is no definitive size given.
  • She has a boy's name due to being named after her male mother, Eisuke Inukai.
  • According to her, both of her parents are gay men who aren't related to her by blood.
  • Isuke usually wears heels which add about 10cm to her height.
  • She stated that her preferred method of killing is with her own hands, and doesn't like making noise or seeing blood while committing a murder.
  • She was the 1st assassin who sent out a notice with another classmate's name.
  • After Isuke was expelled, there were red carnations on her desk, which mean "mother's love". Unlike the others, her flowers were depicted as buds.
  • Isuke Inukai's handgun is a Remington 1866 Derringer.
  • Her hobby is shopping.
  • Her favorite food is caviar and her least favorite food is white bread.
  • She sleeps an average of 8 hours.
  • Inukai means “dog keeper” (犬=dog, inu, 飼=keeper). Isuke is a male name written with the kanji for “I” (伊) and “through” (介, kai).
  • Her type is blue collar workers.