Shuichi Saihara is the deturagonist-turned true main protagonist of Danganronpa V3: Killing Harmony.
He is a student in Ultimate Academy for Gifted Juveniles and a participant in the Killing School Semester. Shuichi has the title of the Ultimate Detective (Super High School Level Detective), though he himself claims he doesn't deserve it, as he is only a "detective-in-training".
He is voiced by Megumi Hayashibara in the Japanese version of the game, and by Grant George in the English version of the game.
After he was accepted to participate in the 53rd Killing Game, Shuichi's memories were fabricated by Team Danganronpa as follows: Shuichi's parents are a famous actor and a screenwriter, who went overseas for business, which is why Shuichi began to live with his uncle and his wife. While Shuichi claims there isn't any sad story behind it all, his parents are neglectful towards him, and he smiles bitterly whenever he talks about them. To show his gratitude to his uncle, Shuichi helped him by working as his assistant in his detective agency. While he was only helping out and had no desire to be a detective himself, he learned to be a detective this way. Shuichi's first detective case was unofficial but a tough one, as his classmate asked him to find her miniature pet alligator, and he had to do a lot of research, prepare tools and eventually climb around mountains and swim up rivers. As thanks for finding her pet, Shuichi's classmate later gave him chocolate for Valentine's Day, though he assumed it was done just as friends. Shuichi was mostly happy to be useful and memorized her words "thank you". His first official case was an infidelity case, which was nothing compared to the alligator one. Most of the cases that happened to come to his uncle were small things like investigating infidelity, but on the one rare occasion Shuichi managed to solve a murder case faster than the police and became publicly known as the junior detective, gaining him his Ultimate title. However, Shuichi does not believe he deserves the title, claiming that he only happened to solve this one case by chance. In reality, the situation was more complicated. When the culprit was captured thanks to Shuichi, his eyes were full of hatred and malice as he looked at Shuichi, and the boy never forgot that gaze. Shuichi heard later that the culprit had killed the victim to avenge his family and the victim was a horrible person who had tricked the culprit's family and driven them to suicide. Shuichi felt guilty for "siding with" the victim and felt everything was his fault because he exposed the truth. He gained a fear of exposing the truth, considering himself a pathetic detective, and he began to wear a hat because he couldn't look at other people's eyes.
Most of the time, Shuichi wears a black cap with three white stripes lining the back of it, and a silver star pinned near the front. Underneath the cap, he has short black hair with a small ahoge. He has very pale skin and a slim figure. His eyes are gambogeish grey, with thick, feminine eyelashes that are completely natural. Shuichi's high school uniform is double-breasted and pinstripe, thin, grey stripes over a black uniform. His pants match his uniforms design, black with a pinstripe design to accentuate his long legs. His former schools emblem is on the breast pocket of his uniform, the pocket accentuated with a dull golden color to stand out from his generally dark, monotone uniform. His shoes are dark blue loafers that are both fashionable and easy to walk in, making it easy for him to investigate comfortably. In the prologue, he wears the uniform of his original high school. He wears a blazer-style casual uniform with jacket, pants and a striped blue necktie. The collar on the shirt is large, making him look more gorgeous. He never lets go of the cap that blocks his sight, regardless of whether or not it goes well with his uniform.
Shuichi appears to be a quite, serious and polite boy. However, he is also stated to have a weak personality, and he is abnormally timid when it comes to speaking. He often has negative remarks, frequently blushes and suffers from a cold sweat. With his unsure demeanor, he has a tendency to assume that other people can do things better than him, and he comes across as quite unreliable at first glance. Among the sixteen students, he is a boy who stands out for his submissiveness but also for his level-headedness. However, Shuichi can also have a stronger attitude at times when the situation calls for it. He is the first to immediately suggest going after the mastermind during chapter 1, and goes to great lengths to trap them, showing an affinity towards proactivity. His hat is an especially sore subject for him and he dislikes to look at other people's eyes, which is why he wears the hat. When meeting Miu Iruma, she accused him of being a pervert with no reason, causing him to angrily yell at her to leave him alone. She had said that boys wear hats to hide their staring, which is obviously very poor reasoning, and Shuichi angrily told her he doesn't need an excuse to wear a hat.