Aguri Yukimura

"If you have only one year left... if you would give your time... Go teach those children... They are lost in dark, just like you... Look at them straight in the eye... and I know you will find your answer.."

- Aguri's final wish to Korosensei

Aguri Yukimura is the former teacher of Class 3-E and the late older sister of Akari Yukimura.

Appearance
Aguri has fair skin and short black hair with bangs that go past her brown eyes, framing her face. She also has a petite body except for her large bust, as it was shown when her sister felt some jealousy of her genes.

Aguri is known for her unusual fashion sense, as it was noted by the original Reaper and many other people, including her students from Class 3-E.

Personality
Aguri is shown to be a very cheerful and clear-minded person, who is truly passionate when it comes to teaching. As a teacher of Class 3-E, she is quite intelligent, being able to teach any subject in spite of chemistry being her first preference. She is also hard-working, having been essentially forced to work as a lab assistant to her abusive fiancé during night hours.

Aguri is also very empathic and perceptive, as when the original Reaper wondered why his apprentice betrayed him, she replied that his apprentice might have wanted his master to "see him", a perception later proved to be tragically prophetic. Her kind behavior was also evident when she went to visit Karma at his house during his suspension.

Comically, Aguri is known for her odd sense of fashion which often leaves others dumbfounded. Despite that, she is remembered very highly by those who knew her and continues to make an impact in their lives.

History
Aguri was the older sister of the young acting prodigy, Akari Yukimura. Prior to the start of the series, Aguri held two jobs: one working as the teacher of Kunugigaoka Junior High School's Class 3-E during the day, and the other as the lab assistant for her fiance, Kotarō Yanagisawa.

One day, Aguri was assigned to be the caretaker of the recently captured master assassin, the Reaper, as none of the other lab assistants were willing to approach the assassin and she was treated as expendable or a "sacrificial lamb" as noted by Yanagisawa. Originally she was meant to be his means of escape, but after saving her from Yanagisawa and learn what 'compassion' was from her, the Reaper befriended her and the two became close as the year went on, to the point that he told her his true past, and Aguri shared her troubles with him. She kept him company and he helped her improve her teaching methods.

When the order to kill the Reaper reached her ears, Aguri decided to warn him of the impending danger and decided to help him escape. Despite this, he didn't listen and was about to use his newfound power to break himself out of the prison. She then tried to convince Yanagisawa to help the Reaper but instead met with a beating from her enraged work superior.

As the building around her was being demolished by the now-omnipotent assassin, Aguri witnessed her colleagues around her being killed by him and as a last resort to calm him down, she hugged the assassin from behind. However, she got caught in the fire of the weapon set up by Yanagisawa and was mortally wounded. Because her wound was too severe to be healed and because the assassin only had the knowledge to kill people, Aguri used her last words to convince the Reaper to not become a genocide machine, instead advising him to become a teacher, continuing her teachings and to never let the students go.

Legacy
Right before the transformed assassin (who would later be called Korosensei) left, her sister Akari witnessed his departure, which caused her to mistakenly believe he killed her sister. Knowing that he would taking over her sister's occupation in Kunugigaoka Junior High School's Class 3-E, Akari arms herself with the tentacles and infiltrates the school with the intention of killing Class 3-E's new teacher Korosensei; this misconception would eventually be cleared up after she finally attempts to assassinate him.

Aguri's last wish would become the primary source of motivation behind Korosensei's desire to teach. As he was transforming into his octopod appearance, Korosensei vowed to continue her work as best as he could.

She is remembered by the class as a kind and cheerful woman who loved teaching, always acknowledged her students, and did her best to encourage them.

Akari Yukimura

 * Main article: Akari Yukimura

Aguri shared a close relationship with her sister. Despite each other's busy schedule with Akari being an actress, and Aguri being a teacher in the day and a lab assistant in the night, they were still able to have their family time together. Aguri was very proud of Akari and sought to watch over her gently from the shadows as she made her way to adulthood. Their relationship was so close that Akari would playfully tease her elder sister and also advised her to end the relationship with Yanagisawa. Aguri's death had a great impact on Akari, to the point that she swore vengeance against Korosensei when Akari believed that Korosensei had killed her elder sister.

Korosensei
Korosensei first met Aguri back when he was human and the master assassin known as The Reaper who had become a guinea pig for Yanagisawa's antimatter experiment. When Yanagisawa needed people to observe Korosensei from a close distance, nobody dared to look after Korosensei since his reputation of being the infamous Reaper scared them. Since Aguri was viewed as disposable, she was appointed by Yanagisawa to look after Korosensei.

Korosensei's first impression of Aguri was that she was his ticket to find a way out but was also annoyed by her bizarre fashion sense. However, as the year passed by, the two got to know each other to the point where the Reaper revealed his personal history to her, and Aguri stating her uphill battle to invigorate her demoralised students. The bond between them was so close that it was implied that Aguri grew to care for him and even have genuine feelings for the assassin. Her care for him led to her attempt to save him by warning that he will be put down following the explosion of the moon.

When Korosensei steadily turned into a monster in his escape attempt (causing Yanagisawa's lab to explode), Aguri held him down to calm his rage and anger, but is fatally wounded by a tentacle mine. Her last words to the assassin would inspire him to become a teacher and continue her work in restoring the confidence and self-esteem of Class 3-E.

Kōtaro Yanagisawa

 * Main article: Kōtaro Yanagisawa

Kōtaro Yanagisawa was Aguri's fiancee. Their marriage was arranged in hopes her determination would rub off on Yanagisawa. As a result, he only saw Aguri as nothing more than a servant and used this opportunity from his status as Aguri's husband to make her do whatever he said. Additonally, he also had little to no consideration for her feelings as he commonly saw other women despite being engaged to her. It was shown that due to Yanagisawa's short temper, he often abused people whenever they annoyed him; Aguri was no exception. In turn Aguri, despite admiring his skills and intelligence, admitted that she couldn't bring herself to love Yanagisawa.

Quotes

 * (To Kayano Kaede) "Well, at least, we have our black hair in common. Ahahaha..."
 * (Her final wish to Korosensei) "If you have only one year left... If you would give your time... Go teach those children... They are lost in dark, just like you... Look at them straight in the eye... and I know you will find your answer."
 * (To Korosensei) "What lovely feelers..! With these hands, I'm sure that you... will become a wonderful teacher..."

Trivia

 * In season 1's premiere episode, Aguri was credited as "Female (Flashback)".