Japanese anime series My Hero Academia has been immensely popular in China. The country is home to countless fans of the manga and anime, which are available on Tencent’s and Bilibili’s platforms. But now the show’s popularity is in jeopardy because of a secret villain whose name references a World War II biowarfare black operation.

In the latest chapter published in the weekly Shonen Jump manga magazine, My Hero Academia reveals the name of a major villain to be Maruta Shiga. Maruta was a Japanese code name for victims of human experimentation during World War II, which killed thousands of Chinese and Korean people.

The apparent reference was immediately highlighted by fans because Maruta Shiga is a mad scientist who also experiments on humans. Subsequently, the character’s surname came into question as a possible reference to Shigella, an E coli.-like germ famously discovered by Japanese bacteriologist Kiyoshi Shiga.

Since the backlash, Tencent and Bilibili have removed the manga from their platforms. Bilibili confirmed the manga was removed “in accordance with China's policies” but didn’t elaborate further. Tencent didn’t immediately respond to a request for comment.

Some anime episodes remain available but got hit with a deluge of negative reviews. On Weibo, posts related to the incident have more than 15 million views, with more than 6,000 posts and comments published over 12 hours.

Chinese fans aren’t the only ones who are upset, either. Some Korean manga fans were similarly outraged.

Maruta Shiga in the story creates a race of genetically-modified golems called Nomu. (Picture:exobaited/Twitter)

Publisher Shonen Jump was quick to respond with a statement saying both the author and the publisher have no intention in referencing “historical events,” adding that the character’s name will be changed in future publications. The author of the manga, Kohei Horikoshi, released his own statement echoing the publisher’s.

My Hero Academia has been a huge success in China. Both the manga and anime have racked up millions of views across multiple online platforms. It even made a crossover appearance in the hit NetEase game Extraordinary Ones.

A villain’s name is jeopardizing that success because the term “maruta” is considered dehumanizing.

Maruta literally means log or timber. During the Second Sino-Japanese War, the Imperial Japanese Army’s Unit 731 -- a covert biochemical warfare division -- used the term to refer to people it was about to experiment on. The facility was disguised as a lumber mill in the northeastern Chinese city of Harbin.

Japanese troops from Unit 731 conduct a frostbite experiment on a live Chinese person on a stretcher in Harbin in 1941. (Picture: SCMP/Xinhua)

Unit 731 reportedly conducted lethal experiments on an estimated 3,000 prisoners, most of whom were Chinese and Korean. The division deliberately infected both male and female prisoners with diseases such as typhus and cholera. Many victims were said to be subject to vivisection without anaesthesia, with some having their limbs and organs removed.

Despite Horikoshi’s pledge of ignorance, some fans cited the author’s tendency to use character names as metaphors in the past as a reason for not believing his statement.

“Kohei used to and likes using characters’ names as metaphor[s]. So coincidence?” a Chinese Twitter user asked.