A Monkey King and a Maiden Fell in Love. For China’s Regulator, It Crossed a Line. Mash-up videos of beloved characters from Chinese classics — some made with A.I. — have caught the attention of the authorities.

In wholesome videos that have delighted the Chinese internet in recent weeks, the Monkey King in a yellow martial arts outfit and a maiden swathed in embroidered silks walk hand in hand. They frolic on sandy beaches and lush forest trails. They ride roller coasters and sample ice cream in a lantern-lit night market.

The unlikely couple are Sun Wukong and Lin Daiyu, who hail from “Journey to the West” and “Dream of the Red Chamber,” classic Chinese novels that were turned into television shows in the 1980s.

The pair had never met in literature — or onscreen — until now. Their love story has been concocted by fans, some using artificial intelligence and some splicing old TV footage together.

While they are popular with audiences in China, the videos have attracted the attention of the authorities, who believe they take too much creative license by bringing characters from disparate worlds together.

An editorial this month in People’s Daily, a Communist Party mouthpiece, acknowledged the appeal of rewriting the destiny of the characters, but said it risked eroding the meaning of the original stories, which are considered among the four most important Chinese classical novels. The editorial called for red lines to be drawn over videos depicting “malicious alterations that ridicule heroes.”Citing a government directive to remove A.I. animations that “seriously violate” the spirit of original works of classical literature and their characters, platforms said in October that they had taken down thousands of videos featuring the Monkey King and Lin Daiyu as a couple, one citing “improper romantic associations” between them.

The two 1980s televised adaptations were the childhood staples of a generation of Chinese millennials, and the characters are beloved for being misfits unbound by convention. The novels have also been reinterpreted into films and operas.

Sun Wukong, the Monkey King from “Journey of the West,” was the irrepressible companion of a guileless monk seeking nirvana. He often found himself in trouble with the gods.

Lin Daiyu was an orphaned girl who had been taken in by wealthy relations in “Dream of the Red Chamber.”Sentimental and sickly, she was prone to sulky ripostes. Ultimately, she died of a broken heart after her lover was married off to another woman.

Liang Ge, a lecturer in sociology at the University of Manchester in Britain, said that the Chinese government demanded a reverential interpretation of the classics and, while the novels had always been rewritten, these retellings seemed to have crossed that line.

The use of the phrase “improper romantic association” by the video platform Kuaishou was telling, the academic added, saying that the authorities seemed concerned by “unauthorized authorship of intimacy at scale.”Some adaptations of the classics have been encouraged by the Communist Party. China’s leader, Xi Jinping, has urged a revival of traditional culture, saying that classic literature is part of the foundation of modern Chinese identity, along with revolutionary heroes. The blockbuster video game, “Black Myth: Wukong,” with hyper-realistic depictions also drawn from “Journey of the West,” was hailed as such a soft power triumph that the tourism authorities in Shanxi Province released a promotional video featuring landmarks that appeared in the game.

Yucong Hao, an assistant professor of Asian studies at Vanderbilt University, said in an email that the freedom to reinterpret Chinese history, mythology and classics remained bounded by “ideological correctness.”“The boundary between telling China’s stories well and telling them in ways that may be deemed subversive is often ambiguous,” she added.

In January, the National Radio and Television Administration launched a campaign to remove A.I. animations that it said maligned revolutionary heroes, presented counterfactual history and misrepresented the spirit of characters from classic literature.

Social media and video streaming apps, including WeChat and Douyin, said in October that they had deleted A.I.-generated videos referencing classical literature that violate the rules.

Afra Wang, a technology writer and cultural critic from China, said that the Lin Daiyu and Monkey King pairing was so popular “because of how different those two characters are, and at the same time, how deeply those two character are baked in the psyche of the generation.”Viewers seemed to enjoy the characters finding happiness together and seeing Lin Daiyu finally content, Ms. Wang said. The most liked comment under the People’s Daily editorial was: “May all great people have great lives. But reality is often so cruel.”Even the Guangzhou Railway posted a commercial comparing its relationship with customers to the chemistry between the pair.

Internet users have largely mocked the removal of the videos. One joked that all relationships that make women happy are labeled “inappropriate romantic associations.”Eileen Chengyin Chow, a Sinologist at Duke University, said that with Mao Zedong identifying himself as a havoc-wreaking Monkey King in 1961, reinterpreting the canon was a political exercise dating back to the early days of the People’s Republic of China.

“Fans feel — rightly so — that it is very much in their rights to reinvent the classics,” she wrote in an email. “After all, ‘who doesn’t want Daiyu to be happy?’ seems to be the most popular sentiment!”Siyi Zhao contributed research in Beijing.