Tetsuto Uesu is a Japanese novelist and editor known for creating several light novel series that have been adapted into manga and anime. He was born in Hokkaido Prefecture. His career as a published author began in 2008 when his work Megane-HOLIC Shindoro~mu won the 2nd Novel Japan Award of Excellence, an award presented by HJ Bunko. He wrote this initial novel under the pen name Tetsujin Ueisu, and it was later republished under the HJ Bunko label with the new title Kanojo wa Megane-HOLIC.

Uesu gained wider recognition with two of his subsequent light novel series. The first, Aesthetica of a Rogue Hero, was published in 11 volumes from 2010 to 2013 with illustrations by Tamago no Kimi. This series was later adapted into an anime television series. His most commercially prominent work is The Testament of Sister New Devil, a light novel series published under Kadokawa Shoten's Sneaker Bunko imprint. The series ran for 13 main volumes and two side story volumes from 2012 to 2021, featuring illustrations by Nekosuke Ōkuma.

As the original creator, Uesu's works have served as the foundation for multiple media adaptations. The Testament of Sister New Devil was adapted into two anime television seasons. The first season, simply titled The Testament of Sister New Devil, aired in 2015, followed by a second season, The Testament of Sister New Devil Burst, later that same year. An original video animation finale, The Testament of Sister New Devil Departures, was released in 2018. In addition to the anime, Uesu's story was adapted into two separate manga series. One serialized in Monthly Shōnen Ace with art by Kashiwa Miyako, and another titled Sister Devil Storm serialized in Young Animal Arashi with art by Fumihiro Kiso. Uesu is consistently credited as the original creator or as the author of the original light novel in the production credits for these anime adaptations.

The thematic elements across Uesu's notable works often blend fantasy action with supernatural settings. Both Aesthetica of a Rogue Hero and The Testament of Sister New Devil feature protagonists who engage in battles involving heroes, demons, and other mythical beings. A recurring element in his storytelling is the presence of contractual or servitude relationships between main characters, often with romantic and comedic undertones. His artistic identity is closely tied to the light novel genre, where his narratives are designed to be complemented by illustrations and adapted into visual media.

Uesu's significance in the industry is marked by his early award win and the successful multi-platform expansion of his series. The Testament of Sister New Devil, in particular, achieved recognition as a notable title within Kadokawa Shoten's Sneaker Bunko imprint, leading to a complete anime adaptation and multiple concurrent manga serializations. Following these successes, Uesu began a new light novel series titled Yarisugita Majin Senmetsusha no Shichi Daizai Yūgi, published by Kodansha with illustrations by the animation studio GoHands.