Kenji Saidō is a Japanese creator known for his work as an original anime creator, manga author, light novelist, and scenario writer for video games. He first came to public attention as the winner of the Animax Award, an annual scriptwriting competition, for his original screenplay titled Shoka. At the age of twenty-four, Saidō's script was selected as the grand prize winner from over twelve hundred entries in the competition's seventh year, which led to it being adapted into an animated special by the acclaimed studio Production I.G. The resulting anime, also called Shoka, premiered on Animax in March 2010 as a single twenty-four minute episode. The story is a historical fantasy set during the Tokugawa shogunate in Edo-era Japan, centering on a clan of warriors who use artistic techniques, specifically calligraphy and drawing, to bring creatures to life and battle giant monsters threatening the city. For this production, Saidō is officially credited as the original creator and also as the screenplay writer.

Beyond his debut anime work, Saidō has established a significant career in the Japanese entertainment industry, primarily as a writer for various media. He has written scenarios for numerous adult visual novels and bishōjo games, including titles such as Aozora no Mieru Oka, Akane-iro ni Somaru Saka, and Shukufuku no Campanella. He also moved into light novel authorship, publishing series like 101-banme no Hyaku Monogatari and Shiinamachi-senpai no Anzenbi under the MF Bunko J imprint. However, his most commercially successful and internationally recognized work is the manga series Trinity Seven: 7-nin no Mashotsukai, for which he serves as the original story author, with artwork provided by illustrator Nao Akinari. The series, a fantasy action comedy centered on a young magus and a group of powerful female mages, has spawned multiple anime adaptations and spin-offs. His other manga credits include the original work for REDNIGHT EVE and Goodbye! Isekai Tensei. In addition to his writing roles, records indicate that Saidō has also performed computer graphics design work for anime productions, including the film No Game No Life Zero and the television series Trigun Stampede. He is also the founder and representative of the adult game company EX-ONE. Saidō's career demonstrates a versatility across the media mix of Japanese pop culture, from winning a scriptwriting contest to becoming the creator of a long-running fantasy manga franchise, but he remains a writer and scenario creator, not a voice actor.