Sunao Yoshida was the pen name of Sunao Matsumoto, a Japanese novelist born on October 24, 1969, in Fukuoka Prefecture. He pursued higher education at Waseda University before earning a master's degree from Kyoto University, where he focused on the study of Chinese history. Yoshida died at the age of thirty-four on July 15, 2004, due to a lung blockage.

Yoshida launched his writing career in 1997 when his debut novel, Genocide Angel: Treason of the Gods, won the Grand Prize at the Sneaker Taisho literary awards, a competition known for its stringent criteria. This early success brought him considerable attention as a promising new talent in the light novel genre, a category of youth-oriented Japanese publishing often distinguished by anime-style cover illustrations.

He is best known as the author of the novel series Trinity Blood, which was serialized in Kadokawa Shoten's The Sneaker magazine. The series is divided into two main story arcs: Rage Against the Moons, which comprises six volumes published between 2001 and 2004, and Reborn on Mars, which comprises six volumes published between 2001 and 2003. An additional volume, Reborn on Mars 7: Aurora's Tusk, was left unfinished. Trinity Blood was later adapted into a manga series and a twenty-four episode anime television series that aired in 2005. After Yoshida's death, a collection of his remaining plots, data, and unrecorded short stories for the series was released as a guidebook titled Canon: Theological War.

Beyond Trinity Blood, Yoshida is credited as the original story creator for the anime project Neppu Kairiku Bushi Road. The project was initially announced in 2003 as a collaboration between Studio Gainax, Takara, and Broccoli, with plans for it to become a television anime movie in 2005. However, it was put on indefinite hiatus after several staff members left the production. The project was revived one decade later, with Bushiroad president Takaaki Kidani credited as the original concept creator and executive producer, while Sunao Yoshida retained his posthumous credit as the original story creator. The completed anime, a fantasy mecha story set in a post-apocalyptic world, was produced by the studios Kinema Citrus and Orange and aired on New Year's Eve in 2013.

Following his death, a memorial exhibition called the Sunao Exhibit was held in his home village of Ashiyamachi, Fukuoka, from January to October 2006. The event was organized in conjunction with his publishers Kadokawa Shoten, Gonzo, and Broccoli to celebrate his creative achievements. In June 2010, his bereaved family donated his works and manuscripts to the library in Ashiya-machi, which subsequently created a dedicated memorial space.