Sugaru Miaki is a Japanese novelist and manga writer, born in 1990 in Iwate Prefecture. He first began posting original short stories anonymously on online message boards around 2011 under the name Genfuukei. These early web serializations included works that would later form the basis for his professionally published novels, such as Starting Over, Azure and Claude, and the story known as I Sold My Life for Ten Thousand Yen Per Year, which was originally titled Three Days of Happiness. His professional debut came in 2013 when Media Works Bunko published Starting Over and Three Days of Happiness. The latter became a significant commercial success, selling over 120,000 copies.

Miaki is best known for writing bittersweet romance and drama stories that often incorporate supernatural or speculative elements into otherwise realistic contemporary settings. His most internationally recognized work is the novel Three Days of Happiness, about a despondent young man who sells most of his remaining lifespan for a small amount of money and is observed by a mysterious clerk during his final months. This novel received a manga adaptation titled I Sold My Life for Ten Thousand Yen Per Year, illustrated by Shoichi Taguchi. The manga was serialized in Shueisha's Shonen Jump+ from August 2016 to October 2017 and compiled into three volumes. Other notable original works include Parasites in Love, Your Story, and Azure and Claude, the latter of which was adapted into a manga with illustrations by artist loundraw and published in 2016.

Several recurring themes define Miaki's artistic identity. His protagonists are frequently disillusioned young men who lack motivation, live isolated lives, and grapple with feelings of regret, loss, and self-worth. Many stories explore the measurable value of a human life or the weight of past choices. Miaki has written extensively about the concept of the summer complex, a melancholic feeling evoked by imagery of an idealized summer that one has never personally experienced. His narratives often prioritize psychological depth and emotional atmosphere over complex plot mechanics, and he has cited films featuring gloomy characters as influences on his work.

Within the industry, Miaki holds significance as an author who successfully transitioned from anonymous online publishing to mainstream commercial success. His novel Your Story was nominated for the 40th Eiji Yoshikawa Literary Newcomer Award in 2019. His works have been translated into multiple languages and published internationally, including English editions released by Yen Press. The manga adaptations of his stories, published through major labels like Shueisha and Delcourt, have introduced his writing to a broader audience beyond light novel readers. His frequent collaboration with prominent illustrators, including loundraw and Shoichi Taguchi, has further extended his influence within the manga and anime creative community.