Saiya is credited as the original creator for two anime works from the early 2000s. The first is the original video animation Ayatsuri Ningyō. The second is the OAV Binetsu Hime: Zange no Shō, released on March 18, 2001, for which Saiya is listed as the original creator and Jun Fujiwara served as director.

A professional manga creator using the pen name Rena Saiya has been active for over a decade, and it is possible that this represents the same individual under a new professional name. The name Saiya is derived from the kanji characters 祭 (sai), meaning festival, and 矢 (ya), meaning arrow. This creator has stated that after several years of working with major Japanese publishing houses, she began using Rena Saiya as her primary pen name. During her time with a major publisher, she produced twelve manga books.

As Rena Saiya, her creative identity is defined by her role as a mangaka who both writes and illustrates her own stories. She has described this dual role as central to the profession in Japan, noting that creating both the narrative and the art allows a creator to present a singular personal vision. Her professional experience includes teaching manga creation at a vocational school in Tokyo. Her published works under this name span genres, including fantasy, comedy, and manga for boys, though she has noted a personal aversion to creating extremely sexual or cruel content. Her published output includes instructional books such as Manga Art for Intermediates and Chalk Art Manga, the latter created with author Danica Davidson, which focuses on drawing manga characters with chalk.