|Voice Actor (jp)||Fumiko Uchimura|
Haruki Sagae (寒河江 春紀; Sagae Haruki) 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 at Myōjō Academy, who was in a competition with the other students who were trying to kill Haru Ichinose where the reward was anything the assassin wishes for. She joined the Black Class because she needed money to support her siblings and her mother, who was hospitalised. The reward she requested for was for her family to be fed for the rest of their lives, even if she had died.
At end the story, Haruki gets a job as a construction worker. In the manga it is revealed that Haruki and Isuke are dating in the end while in the anime's ending she's seen with some equivalency exam instructions she has with her- Judging by this scene she may plans to send herself and her siblings to school.
She was the third assassin to attempt an attack on Haru Ichinose. She used Tokaku's name in a memo to call Haru into the gymnasium, where she would personally hand Haru the advance notice with her name and attendance number on it. She then started to strangle Haru from behind using her garrote wire. However, Tokaku showed up, cutting the garrote wire from afar using one of her throwing blades, then knocking Haru out of the way. The two assassins then began to fight, Haruki with an iron knuckle glove and Tokaku with throwing blades. The two seemed to be even but that was shortly before Tokaku got serious and overpowered her. Haruki refused to give up, even though she had lost. She then confidently said, I win as she cut a wire of a trap she had set, intending to take out the three of them using the lighting fixtures at the top of the gymnasium. However, they all survived but Haruki appeared to become incapacitated with a broken arm and neither of them with any fatal wound. She became the third student to be expelled from the Black Class.
After the Black Class officially disbanded Haru and Tokaku are seen receiving their diplomas and Haru even taking the diplomas of the 11 other former students of their class and went on a journey to give each (ex-) assassin their earned diploma. During that scene it's shown (in the manga) that Haruki, who's now working as a construction worker, received a call from from her lover. Co workers of her ask if that's her bodyfriend.
The next panels switching over to a beach scenery where Eisuke can been seen together with his daughter Isuke who 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 Isukes simply replies with saying she just loves Haruki and can't help it.
She is a tomboyish yet fashionable girl who is always shown eating snacks, especially Pocky. She is also the typical lazy student who sleeps during class. She is always looking for thrills, but is very sensitive about her family's safety.
In addition, she is seen to have a strong will to fight when she wants to achieve a certain goal as seen when she lost to Tokaku Azuma but never gave up, even going as far as trying to kill Tokaku, Haru and herself, in order to succeed.
She has long red hair tied up in a ponytail with barrettes on her bangs. She wears a beige jacket over her school uniform which is a white shirt and a red plaid bow and skirt, along with white socks and brown shoes. She usually wears bracelets and a purple hair tie on her right wrist. She wore long studded fingerless gloves before she attempted to kill Haru.
Skills and Abilities
She uses a garrote wire to carry out assassinations. It is used to strangle her victims and it is very effective despite the low chance of actually catching a person from behind with it, which is very useful in stealth jobs.
However, her physical assassination skills make up for that because they are exceptional. She wears a type glove that has a iron spiky surface at the top, which is very deadly if a person receives a hit. Her fighting skills are on a high level as seen when she was engaged in hand-to-hand combat against Tokaku Azuma, who was using throwing knives and they were evenly matched. In the end, Tokaku got serious and dominated Haruki in their fight when she realized she was about to be sacrificed.
Not much is known about her past except the fact that she came from a poor and large family with a sick mother and without a father figure in the household. She worked as an assassin to help provide for them.
- She and Nio Hashiri both wear bows with their uniforms.
- She has 9 younger siblings. One of her siblings' name is Fuyuka.
- She wanted to buy a table of a smiling family after she got her first pay check from an assassination job.
- When she got her first pay check, she also bought a bottle of pink nail polish. She says that it doesn't suit her at all but she actually likes it. Even before her assassination attempt on Haru, she painted her figure nails with a bottle of it.
- She was the first assassin to personally give Haru the warning letter with her name and attendance number on it.
- When she was expelled from the Black Class, there were verbena flowers on her desk, which symbolize family love. 
- Her favorite snack is Pocky.
- Her ending theme song is どうってことない sympathy (Dou tte Koto Nai Sympathy). The song is performed by Fumiko Uchimura as Haruki Sagae.