Yuuichi Katagiri

Yuuichi Katagiri (片切友一, Katagiri Yūichi) is a sophomore in high school. He is a poor student who lives alone and works part-time to make a living. He values his friends more than anything else, following his mother's advice that "friends are more important than money". An incident leads him to get involved in an unreasonable game of paying off debts.

Appearance
As a child, Yuuichi had scruffy, short black hair. As he got older, he began to grow it out more and now has longer bangs.

Child Yuuichi tended to wear a regular t-shirt. During the various versions of Tomodachi Game, older Yuuichi has either worn his high school uniform (Secrets Game - Shibe's trial), the uniform of the game (Prison Game), or a long black jacket over a t-shirt and pants (all other periods).

Yuuichi is relatively tall and fairly lanky. Facially, Yuuichi has some of the sharpest features in the series, with his jaw, eyebrows, and eye shape all being well-defined. He also has some of the most varied expressions. When having touching moments with his friends, he has shown softer and more happy faces. However, he has an insane slasher smile that is often brought out when he gets serious in a game.

Personality
At the beginning of the story, Yuuichi appears to be a diligent and happy student, who works hard to be able to join his friends on the school field trip. He values his friends heavily throughout the story. He shows kindness and a willingness to self-sacrifice for the sake of his friends, even going so far as to brand himself the traitor in order to prevent further discord.

As the story progresses and the games become more and more serious, however, Yuuichi begins to show a much more sinister side. This dark nature is likely the result of his troubled upbringing by an adopted mother who had to sell her body and a con man/swindler who served as a father figure and teacher. He shows little remorse for any of his more devious actions and appears sadistic at points when he takes pleasure in the misfortunes of his enemies. He is not above using any particular means to achieve his goals, such as threatening to murder Kaidou or using Kokorogi to blackmail a teacher.

History
Yuuichi Katagiri's past is somewhat a mystery currently, although it is known that Yuuichi has murdered three people and he has no idea who his real parents are. He was raised by his adopted mother Yuka Katagiri who had to sell herself to make money, which is a traumatic memory for Yuuichi. He also had a father figure in the form of a swindler named Taizen Shiba, who taught him various psychoanalytic techniques and mentalist tricks. Though he uses these to great effect throughout the series, he does not respect Taizen in his memories. He seemed to look up to him as a child, but he calls him a devil and scum at various points in the story. When trying to get Satone to back down from their game, he reveals that Taizen is one of the three people he's killed.

At some point after he killed Taizen, he rejoined the "normal world" and began attending school while making paper flowers to support his living expenses. After entering high school, he eventually became friends with Shibe, Tenji, Shiho, and Kokorogi. This circle was maintained well until the Tomodachi games began.

At some point during his childhood he founded the Tomodachi game

Plot
Yuuichi finishes delivering the newspapers, and his boss remarks he did double what he usually does. After turning in the money at school, his friend Shibe comments he could have lended Yuuichi the money if necessary. Later in the day, he gets a letter addressed from Shiho, asking him to meet her at the school gates at a certain time. He arrives late, and sees all his friends gathered, and he asks them why they are there. They are all confused, and say he was the one who invited them. He takes their letters, and becomes worried, but before he can do anything, he is hit from behind and sees his friends dragged away.

He wakes up in a blank room, with his friends. They are all confused what had happened, but then a cartoon character comes out and greets them. Yutori notes he is Manabu, a character who is known to steal from his friends from a children's cartoon show. Makoto tells them one of their friends has 20 million yen worth of debt, and if they choose to leave the 2 million yen entrance fee paid would not be returned, so the person would keep the debt. Yuuichi is about to ask who did this, when Shiho comments that since they're friends, there's no reason to ask or doubt, and everyone ends up agreeing to play the game.

Intelligence
Yuuichi could be considered one of the most if not the most intelligent character in the series. Despite his intelligence and triumphant win over Kei Shinomiya, he claims that the latter is way more better than him in terms of cognitive skills. He states that he didn't win because he was smart. His school grades are much lower than even Makoto Shibe.

His ability to manipulate people and form complex plots around these manipulations is extraordinary. Yuuichi often allows himself to be underestimated by his adversaries as a means to deceive them. While perhaps not as technically knowledgeable as Tenji, Yuuichi has a wealth of practical knowledge and a deep understanding of the shady underworld. His machinations are rarely seen through unless they are allowed to be revealed as a part of a grander scheme.

Ruthlessness
Though perhaps not an ability in the common sense, Yuuichi's absolute ruthlessness is a key factor in his success throughout the series. He does not hesitate to threaten others or carry through on those threats for the sake of his goals. To this extent, many characters have described Yuuichi as "evil", "horrible", "monster", and "devil".

Athletic Ability/Pain Tolerance
Yuuichi has briefly shown decent athletic ability in terms of running and knocking others down in short scraps. What is more impressive, however, is Yuuichi's insane tolerance for pain. This is primarily highlighted in the Weakling Game against Kuroki. Yuuichi manages to maintain his composure and his plot to destroy Kuroki despite being puched three times, having three nails torn off, and having his hand stabbed clean through with a knife. He also broke his own finger without so much as a peep when cornering the Captain of group K in the Hide and Seek game.

Etymology

 * The name Yuuichi means "friend, companion, pal" (友) (yuu) and "one" (一) (ichi).
 * Yuuichi's surname Katagiri means "one-sided cutting" (片切).