Shimoku Kio is a Japanese manga artist born in 1974, best known as the creator of the series Genshiken. He is a graduate of the University of Tsukuba, where he majored in Japanese painting within the art program. His professional debut came in 1994 during his university years when his short story Ten no Ryoiki (The Domain of Dots) won the Afternoon Four Seasons Award and was published in Monthly Afternoon magazine. Following his debut, he published several short works and serializations that focused on university student life, including the short story Kagerou Nikki in 1995 and the serialized works Yonensei (Fourth-Year Student) from 1997 to 1998 and its sequel Gonensei (Fifth-Year Student) from 1998 to 2001. These early works explored the relationships and uncertainties of young adults navigating their final years of school and early professional life.

Kio achieved his breakthrough and remains most recognized for creating Genshiken, which was serialized in Kodansha's Monthly Afternoon magazine from 2002 to 2006. The series follows the daily activities of the Society for the Study of Modern Visual Culture, a college club for fans of anime, manga, and video games, at the fictional Shiiou University. The manga was later published in English by Del Rey Manga. The series received two anime television adaptations; the second season in 2007 featured scripts co-written by Kio himself alongside writer Michiko Yokote. He later resumed the series with Genshiken Nidaime, also known as Genshiken Second Season, serialized from 2010 to 2016, which followed a new generation of club members after the original characters graduated.

Within the world of Genshiken, the characters are fans of a fictional anime and manga series titled Kujibiki Unbalance. This story-within-a-story was first adapted into a three-episode original video animation. In 2006, it was developed into a full, standalone twelve-episode anime television series titled Kujibiki Unbalance, which featured redesigned characters and a new plot distinct from the version seen in Genshiken. A manga adaptation of this version was also produced from 2006 to 2007, with Kio serving as the original creator and writer, while the illustration was provided by artist Keito Kome.

Kio has stated that he is an otaku himself, and a central goal of his work, particularly Genshiken, has been to portray otaku as normal human beings rather than as a strange or deviant subculture. He has expressed ambivalence about the mainstreaming of otaku culture, noting a sense of personal shame regarding the identity even as he works to humanize it. This nuanced, introspective, and largely realistic approach to depicting fan subcultures and the lives of young adults is a hallmark of his artistic identity. His characters are often depicted with an unflinching honesty and tenderness as they navigate their hobbies, personal relationships, and career paths.

Beyond his most famous series, Kio has created other manga works. In 2008, he wrote and illustrated Digopuri (also known as Jigopuri or Hell's Angels), a story about twin sisters raising a baby in their apartment. In 2009, he began serializing Spotted Flower, a series widely considered a spiritual successor to Genshiken that follows adult characters navigating marriage, work, and family life. From 2018 to 2022, he serialized Hashikko Ensemble, a comedic story about a high school choral club. Kio remains an active figure in the manga industry, known for his influential portrayal of geek culture and his detailed, character-driven storytelling.