Marvel Comics’ new editor-in-chief, CB Cebulski, has come under fire after it was revealed that he had written under the alias Akira Yoshida.

Cebulski, who was appointed earlier this month, confirmed to the comics site Bleeding Cool on Tuesday that he had spent “about a year” writing comics under the Japanese pseudonym Akira Yoshida.

Bleeding Cool’s founder Rich Johnston said he first asked Cebulski, who is Caucasian, if he was masquerading as Yoshida in 2006, when Cebulski was associate editor at Marvel, but he “denied it, telling me that Akira Yoshida was an actual person”, citing numerous office visits and convention appearances as proof. Yoshida, who is listed at Marvel.com as a writer for series including X-Men and Wolverine, was even interviewed by the site Comic Book Resources in 2005, providing a fictitious biography about a childhood in Japan, employment at a small Japanese comics publisher, and his introduction to American editors.

According to Bleeding Cool, Cebulski had dreamed up the Yoshida pseudonym while working at Marvel, which did not publish comics written or drawn by staff members. “Yoshida” initially wrote for the publishers Dark Horse and Dreamwave, before an editor at Marvel approached him, unaware of who he really was, and signed him up. Numerous Marvel staffers had confirmed to Johnston that they had met Yoshida – but it turned out they had in fact met a visiting Japanese translator.

The story was reignited on Monday, as Cebulski prepared to take up his new role at Marvel, when Image Comics’ David Brothers tweeted: “We should definitely be asking Marvel and new EiC CB Cebulski on why he chose to use the pen name Akira Yoshida in the early 2000s to write a bunch of ‘Japanese-y’ books for them”.

After what Johnston described as a “social media fire”, Marvel’s new boss admitted to the comics writer that he was, in fact, Yoshida. “I stopped writing under the pseudonym … after about a year,” Cebulski said. “It wasn’t transparent, but it taught me a lot about writing, communication and pressure. I was young and naive and had a lot to learn back then. But this is all old news that has been dealt with, and now as Marvel’s new editor-in-chief, I’m turning a new page and am excited to start sharing all my Marvel experiences with up and coming talent around the globe.”

According to Johnston, the fact that Cebulski wrote as Yoshida about Japanese characters, locations and themes raised issues of “appropriation, yellowface, and playing up an authenticity that wasn’t there”.

“He was hired by some to provide an authentic Japanese voice,” Johnston wrote. “And as much of a massive fan of Japanese culture as Cebulski was, with family in Japan and living in Japan on and off since he was 20 years old, and who began his professional comics life editing manga – he just wasn’t that.”