Koji Inada is a Japanese manga artist born on March 14, 1964, in the Nippori district of Arakawa, Tokyo. Before entering the manga industry, he graduated from the Tokyo Metropolitan College of Aeronautical Engineering. He initially set aside his artistic aspirations to pursue engineering at his parents’ request but decided to become a manga artist after completing his studies. Inada began his career as an assistant to notable creators such as Masakazu Katsura.

Inada is best known for his long-running collaboration with writer Riku Sanjo. Their most famous work together is the fantasy manga Dragon Quest: The Adventure of Dai, which was serialized in Shueisha’s Weekly Shōnen Jump from October 1989 to December 1996. Inada was approached to illustrate the series by editor Kazuhiko Torishima, who initially envisioned a manga based on the popular Dragon Quest video game franchise. Inada turned down the offer, preferring to create his own original series, but eventually accepted when told he would be dropped as a client if he refused. The series became a major success, with over 50 million copies in circulation, making it one of the best-selling manga series in history. The manga was later adapted into two anime television series, the first airing from 1991 to 1992 and a second 100-episode reboot airing from 2020 to 2022.

Following the conclusion of The Adventure of Dai, Inada and Riku Sanjo reunited to create Beet the Vandel Buster. The series began serialization in Monthly Shōnen Jump in 2002. The manga went on an extended hiatus in September 2006 because Inada fell ill. After a lengthy recovery, he returned to work on the series, which resumed publication in 2016.

In addition to his work on long-form serializations, Inada designed the characters Meiro and Damudo for the 2020 arcade game Dragon Quest: The Adventure of Dai – Xross Blade. This game and its related media are part of the larger Dragon Quest franchise that his original manga helped expand. His other credits include a one-shot titled Iruka Iwa de... from 1998 and a short story collection from 1988 called Kusottare Dazee!!. For a period, he also drew the Dragon Quest IV Gaiden: Jigoku no Meikyū manga with story by Riku Sanjo, published from 2001 to 2002. His artistic style is closely associated with the visual aesthetic of the Dragon Quest series, and his work has been noted for its dynamic action sequences and fantasy adventure themes.