Rihito Takarai is a Japanese manga artist and illustrator known for works in the boys' love genre. Born on October 17, her career began with doujinshi (self-published works) based on popular series such as Naruto and The Prince of Tennis before transitioning to commercial publications in 2004, when she began illustrating novel covers. Her professional manga debut came in 2006 with the series Seven Days, based on a story by橘紅緒, which was published in the magazine Craft and later collected in 2007. Following this success, she created original manga including Only the Flower Knows, which started in 2009, and Hana no Miyako de, which began in 2012. Her most internationally recognized work, Ten Count, was serialized in the magazine Dear+ from 2013 to 2017. The same year, she launched Graineliers in Monthly G-Fantasy, a notable departure into the fantasy genre and shonen demographic under the pseudonym Octo. Beyond manga, she has provided illustrations for numerous novels and produced the art collection Mirror in 2015.

The anime adaptation of Ten Count has a notable production history. Initially announced as a television series slated for 2020, the project faced delays and was subsequently redeveloped as an animated film scheduled for theatrical release in 2023. However, in January 2024, the production committee officially announced the cancellation of the film project due to unspecified production issues, leading to the closure of the official website and social media accounts. No alternative production has been announced. Takarai also contributed original character designs for the 2019 anime series Try Knights.

Takarai is recognized for a distinct artistic style characterized by delicate, refined linework and elegant character designs, often featuring bishonen with slender, androgynous silhouettes and expressive facial details. Her narratives frequently explore psychological depth and emotional restraint, focusing on intimate character relationships and personal obstacles. In the boys' love genre, she is regarded as a significant creator whose works have achieved international popularity and commercial success, with Ten Count becoming a signature title that expanded her readership globally. Her ability to work across demographics, from yaoi to shonen with Graineliers, demonstrates her range and influence within the manga industry.