Kouko Kaminaga
Kanji 神長 香子
Rōmaji Kaminaga Kōko
Occupation Student (former)


Attendance No. 3
Gender Female
Age 16
Status Alive
Debut Appearance
Anime Episode 2
Manga Chapter 4
Voice Actor
Voice Actor (jp) Haruka Yoshimura
Image Gallery

Kōko Kaminaga (神長 香子; Kaminaga Kōko) is one of the main characters of the manga and anime series Akuma no Riddle. She is a former student at Myōjō Academy and of its 10th year's Black Class who was in a competition with the other students of that class who were trying to kill Haru Ichinose where the reward is anything what that assassin may want. The reward she wanted was to quit assassination. Before her expulsion, she held the position of class representative, which she passed to Suzu Shutō afterwards.

In the final chapter Kouko's shown holding a loaded handgun and luring behind a corner, apparently awaiting a target which she can kill thus this panel implies that she's still an assassin after the black class disbanded.

In the final episode, she is seen being chased by two nuns and she shoots them both. She is wearing Irina's crucifix necklace. It is hinted that she'll kill all the assassins in the orphanage where she grew up in order to escape from them and gain her freedom.

Assassination Attempt

She was the second assassin to attempt an attack on Haru Ichinose. She wanted to quit being an assassin as a reward which is very ironic as Tokaku Azuma said but it may have been suggested that she was forced into participating by her organization. She first set bombs inside of the target's refrigerator; Haru saw through the first trap, a frag grenade hidden behind apples in the fridge and then Tokaku saw through the second, which was a pipe bomb hidden in grape soda, so both attempts failed. Later, when Haru was curious in finding a secret room at the library, both her and Tokaku were bombed after Haru noticed a charm she gave in one of the books but Tokaku protected Haru from the flames/explosion and suffered slight burns to her back and she was also stunned for a brief moment. After that failed, Kouko fired a few rounds from a gun but they all missed; Tokaku then threw knives at her but also missed. After Kouko realized that her gun was out of bullets, she ran out of the secret room but Tokaku ran after her, being blinded a little by a smoke bomb that Kouko triggered. When Tokaku caught up to her, the two fought but Kouko was no match and just lost her will to fight. After that, she became the second student to be expelled.


Kouko has a serious nature and lacks in emotion most of the time. Additionally, she appears to hold a large amount of guilt for causing the death of her mentor Irina.


She wears round oval shaped glasses and also has long straight black hair that she keeps in twin tails with curls at the bottom and has light blue eyes.

She usually wears a long blue and white dress. During her assassination attempt, she also wore Irina's crucifix necklace.

Skills and Abilities

Although her grades were the best in the class, she's poor at physical assassination skills. However, she is a really smart and skillful individual who uses her brains quite resourcefully as seen when she drew up a blue print plan for the entire dorm where the entire Black Class stays in. She is also a bomb specialist, where she can create and set a trap almost anyhow using any types of bombs.


When she was a child, she got bullied a lot by the other children who were also training to become an assassin at NPO and they would call her clumsy and dangerous. On one of her missions with Irina, she accidentally set the bomb timer early, resulting in Irina's death. She later joined the Black Class to prove that she could succeed.


  • When she was expelled, a red spider lily was placed on her desk. In Japanese and Chinese culture, this flower represents "death". This is symbolism for the "death" of Kouko's role as assassin.
  • Kouko and Suzu Shutou are the only two to use explosive devices.
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