Hiromasa Okujima is a Japanese manga artist and writer, recognized as the original creator of the series Baban Baban Ban Vampire, which has been adapted into both an anime television series and a live-action film. He was born on March 23, 1982, in Shijimi, Hyōgo Prefecture, Japan. From a young age, he was inspired by Dragon Ball and decided to pursue a career as a manga creator. After high school, he attended an art college in Kobe and, at the age of 20, moved to Tokyo to work in the publishing industry. Early in his career, he gained experience as an assistant to Tetsuya Saruwatari, a creator known for combat-focused works, and has also cited Takehiko Inoue as a significant influence.

Okujima made his debut as a creator in 2007 with the series Shout!. His body of work includes a diverse range of genres and themes. Among his notable series are Itadaki! Nariagari Meshi, a culinary story that was nominated for the Tsugi ni kuru manga award in 2018, and the fantasy series Les Racailles de l'autre monde. He has also created works such as Assistant Assassin, the bathhouse-focused comedy Au Bain, les yankees, and Dōsei Yankee Akamatsu Seven, a boys-love series created in collaboration with writer SHOOWA that was later licensed by Viz Media's SuBLime imprint.

Okujima is best known as the writer and illustrator of Baban Baban Ban Vampire. The manga began serialization in Akita Shoten's shōnen manga magazine Bessatsu Shōnen Champion in October 2021. The series was still ongoing as of late 2024, with its ninth compiled volume released in December of that year. Its commercial success led to the announcement of two major adaptations in February 2024: an anime television series produced by Gaina and a live-action film. The anime premiered in January 2025 and is distributed internationally by Netflix, while the live-action film is scheduled for release in Japan in 2025.

Recurring elements in Okujima's work often include themes of masculine camaraderie and characters with a delinquent or rough-edged persona, frequently referred to as yankees. His series regularly feature protagonists with a strong sense of loyalty and a penchant for fighting, a characteristic seen in works like Les Racailles de l'autre monde and Au Bain, les yankees. Despite this recurring motif, he has demonstrated versatility by exploring genres such as cooking, fantasy, and boys-love throughout his career.