Keiichi is a teenager who moved to Hinamizawa about a month before Higurashi began.

He has a natural charisma that allowed him to make fast friends with classmates Rena Ryuugu, Mion Sonozaki, Rika Furude, and Satoko Houjou, as well as Shion Sonozaki (who may or may not be a classmate of his depending on the arc).

Despite initially seeming innocent in comparison to his friends, Keiichi actually has a criminal record from when he lived in the city.

Before Hinamizawa Edit

Keiichi attended a cram school in Tokyo, where he was struggling with his grades. An intelligence test he took in class showed that he was actually very smart, but unless he found a question interesting, he would do poorly on it. His teacher called in his parents and had him moved to an advanced/gifted class, where his grades improved rapidly. As a result, he was praised more by parents and teachers and given more allowance, but his classmates began to hate him. His good attitude began to deteriorate as his good grades became expected of him and he recieved less attention.

Keiichi took up an interest in airsoft guns, which he could buy with the extra allowance he recieved from his better grades. He started with shooting cardboard targets, but because of his increasingly rebellious attitude, as soon as he read the warning not to shoot at others, he immediately did just that. Keiichi would shoot children as they were walking home from school, which sent the city board and PTA into a panic. Members of the PTA stood at intersections and children were instructed to walk home in groups.

This behavior continued until Keiichi saw a young girl walking around alone after school and began shooting her with an airsoft gun. Instead of running immediately, she turned around and he accidentally shot her in the eye. Unable to help her without giving himself away, he left her where she was unattended. His resulting guilt from the incident caused him to later come down with a fever and, unable to sleep, he turned himself in with his parents and the police. Because of Keiichi's dad's job as an artist, they were able to pay off the settlement money and he was only put on probation. He moved to Hinamizawa both because of his dad's job as an artist, and as a way of starting over.

Keiichi's past was alluded to in Tatarigoroshi-hen and revealed in Tsumihoroboshi-hen.