Rei Kindaichi

Rei Kindaichi (金田一 零) is a former student at Hope's Peak Academy's Class 78th and participant of the Killing School Life. Due to his overwhelming ability in programming area, he attended as the Ultimate Programmer (超高校級のプログラマー, lit. Super High School Programmer).

Appearance
Rei is considerably shorter than his classmates and has a very pale complexion, white hair with a purple tint and long bangs separated by a hairpin that obscure the left side of his face which was. Although quite thin, Rei is somewhat capable of defending himself. He wears a white buttoned shirt, white tie, black sleeveless vest and pants and leather boots. When disguised as a regular player at the killing game, Rei wore a white rabbit kigurumi, but as he is revealed to be the mastermind, he started using a Monokuma kigurumi instead. After killing Hikaru Aino, he now uses her coat as a memento.

Personality
Rei is presented as an antisocial, quite agressive young boy. Excluiding Mitsuru Kudo, he didn't appear to get close to anyone, even with Yukio Shizukane who really tried to understand him and befriend him. Although he sounds spoiled, everyone admits that he is very useful with his theories about the game and Monokuma itself. After Anna Kiryuin's death, Rei started to develop socially as he was apt to talk with others more easily. He even showed some humanity when he apologized to Yukio due to his early behaviour with them, promising him that he would try harder to be a better person.

It was everything in vain, though. Once Yukio discovered that Rei was the true perpetrator of both The Tragedy and the Killing School Life where most of his friends died, he started hating him but that attitude didn't annoyed Rei at all. It is revealed that he was diagnosed with psychopathy, admiting that he didn't feel any remorse for what he did to all of his classmates and world.

Rei is almost always seen with a arrogant smile in his face but actually, he is bored about everything. Even though he accepts being called the Ultimate Despair, he doesn't consider himself as the symbol of despair, as even despair does bore him even more than hope. Rei describes himself as an empty shell who wants to feel something. He lacks any empathy and doesn't care about anyone despite himself, even killing his childhood friend without a second thought as he considered that she wasn't useful to him anymore and found her death utterly boring (she accepted it too easily, according to him).

As noted by the Future Foundation, Rei is dangerous because he can mask his thoughts and goals with noble words. He could easily make the children of the Warriors of Hope work for him and manipulated them to kill the adults, using the pretext of their tragic pasts to do so. He finds the world too boring and considered killing himself but ultimately found this boring, too. Rei is very intelligent and smart as the creator of the powerful artificial intelligence of Monokuma which could continue the game even if he could be dead. His second talent, Ultimate Analytical Prowess (超高校級の分析力), reflects his power to easily predict people's acts and thoughts through observation and calculations, being one of the reasons to find everything and everyone boring as they are predictable. He correctly predicted that Mitsuru would kill Amaya to protect him and got really angry with him due to that.

He is merciless and although he hates to take action himself at killing, he can do it if the situation calls for it. Rei doesn't have any standards and do whatever he thinks it would be interesting. The most unpredictable, the better. He also finds relationships boring and doesn't understand anything about love or friendship at all, just doing it for the sake of his plans and not to actually enjoy real feelings.

Rei is usually emotionless but is a very good actor. He is seen as an older brother by the kids even though he doesn't care about them dying, letting them be and do whatever they want as long as they entertain him at the minimum.

Creation and Development
Miika wanted to do an eccentric one for the programmer title. Even though she admits that she likes Chihiro Fujisaki's personality, she imagined a programmer to be quite agressive because of how he may lives. Rei's role as the mastermind wasn't decided until she thought that a programmer could do a more powerful Monokuma than Junko Enoshima did.

His entire name is merely a reference to the most know computer language, binary code, which uses zero and one. His surname means "one golden rice field" (金田一) and his name means literaly "zero" (零). His birthday is in the same day as when Surveyor 1 landed in Oceanus Procellarum on the Moon, becoming the first U.S. spacecraft to soft-land on another world.

Trivia

 * Rei is very different from his original counterpart, Junko, as he finds everything boring, be it hope or despair. He also didn't exactly planned The Tragedy for the sake of despair, but merely to entertain himself.
 * Rei doesn't have any sexual or romantic drive.
 * His rabbit and Monokuma kigurumi are based on Mukuro Ikusaba's rabbit hairpin in her disguise as Junko and Junko's own Monokuma hairpins.
 * Rei is Miika's favorite character.