Norihiro Yagi is a Japanese manga writer and artist born in 1968 in Naha, Okinawa Prefecture. He began his professional career in 1990 when his debut one-shot work, Undeadman, was published in Monthly Shōnen Jump and won the 32nd Akatsuka Award. His first serialized manga was the comedy series Angel Densetsu, which ran in Monthly Shōnen Jump from 1992 to 2000 and was collected into fifteen volumes. The series was later adapted into a two-episode original video animation produced by Toei Animation.

Yagi is best known for creating the dark fantasy series Claymore, which was serialized from 2001 to 2014, first in Monthly Shōnen Jump and later in Jump Square after the former magazine ceased publication. The complete series spans twenty-seven volumes and one hundred fifty-five chapters. In 2007, Claymore was adapted into a twenty-six episode anime television series produced by the studio Madhouse and directed by Hiroyuki Tanaka. The anime adaptation closely followed the manga for its first twenty-four episodes before concluding with an original storyline. In March 2025, a live-action television series adaptation of Claymore was announced.

Following the conclusion of Claymore, Yagi published a one-shot titled Arcadia of the Moonlight in 2017. Later that year, he began his next serialized work, Ariadne in the Blue Sky, which shifted publication to Shogakukan's Weekly Shōnen Sunday and ran until 2023, comprising twenty-two volumes. In December 2024, he published a dark fantasy one-shot titled The Knight and the Corpse on the Shōnen Jump+ digital platform.

Yagi has discussed his creative approach in interviews, noting that his fascination with European settings, particularly medieval locations in France, influenced the world-building of Claymore. He has stated that the decision to feature female protagonists wielding large swords against monsters was motivated by the visual contrast he found appealing rather than any specific ideological message. Regarding the artistic differences between his major works, Yagi has described Claymore and Ariadne in the Blue Sky as entirely separate in his creative process, with the latter representing a deliberate shift toward a lighter, more traditional shonen adventure tone compared to the darker fantasy of its predecessor. His drawing style is characterized by clean lines, minimalistic facial expressions, and abundant use of halftones. In his spare time, Yagi enjoys listening to hard rock music, playing video games, driving, and practicing martial arts.