Go Nagai is the original bad boy of manga. His series “Shameless School” (“Harenchi Gakuen”) cemented his status as the inventor of the hentai (erotic) genre. “Shameless School” debuted in the very first issue of Shueisha Inc.’s Weekly Shonen Jump, Japan’s best-selling manga magazine, in August 1968. The adult shenanigans and sexualized students Nagai depicted rendered him the target of national media, Parent Teacher Associations and women’s groups — and an infamous artistic pioneer.

Over the past year, both Nagai and Shonen Jump have been celebrated for their 50th anniversary milestones. But one of Nagai’s later achievements has gained immediate relevance. The animated adaptation of his 1972 “Devilman” series, “Devilman Crybaby,” directed by Masaaki Yuasa and released on Netflix back in January, has become one of 2018’s most talked-about anime and biggest international hits, despite its source being 46 years old.

Now 73, Nagai looks like a professor, which, in fact, he is, albeit one with a flair for smart jackets. In 2005, he started teaching character design at the Osaka University of Arts. The soft-spoken former troublemaker admits that he may have been ahead of his time, and is quick to cite Netflix as the reason his work is today being embraced globally.

“‘Devilman’ came out over 40 years ago, and maybe the work itself was too early for the audience,” he tells me over coffee in Los Angeles. “Up until very recently, only one volume was translated into English. I think it’s Netflix that has driven my reputation here in the United States.”

Director Yuasa, 53, was the featured anime artist at this year’s Tokyo International Film Festival. He brings his signature visual contortions to “Devilman Crybaby,” while adroitly updating its specs: characters communicate in rapid-fire text messages and post raw and bigoted opinions in real time on social media sites; a street gang’s disenchantment is sung in hip hop verses; and the story’s principal young women, Miki and Miko, are edgy, self-possessed and impatient, showing nary a trace of anime’s conventional kawaii cuteness, often preferring one another to men.

The result is a dizzying pastiche. When I first saw the Netflix “Devilman” adaptation, I succumbed to binge mode. I couldn’t stop watching its kinetic blend of ’70s-styled debauchery and 21st-century dread, even when the violence and eros bordered on the gratuitous. The series has been praised for its openly gay characters, bold sexuality, nihilism and wit. “Devilman” shows us a world of extremes, in which freedom of expression and the license to commit acts of evil coexist in a world of rampant libertarian chaos.

Yuasa believes that “Devilman” is more germane to the technologies and social rifts of our era than it was when it first appeared.

“Today’s situation is a lot closer to ‘Devilman’ than it was when Nagai wrote it in the ’70s,” he says. “The popularity of social media means people are a lot more connected, for good and bad — like someone getting shot over a video game. We learn about unarmed black people being killed by police, people being tortured and the rise of nationalism in politics. In Japan, too, where a lot of problems are openly blamed on foreigners.

“But it can also help spread good that we wouldn’t otherwise know about. We see people coming out as gay or trans on social media, and there’s a greater opening up and acceptance of different opinions and lifestyles.”

In Japan, Nagai is known for creating two other seminal titles: the groundbreaking shōnen (young boys’) manga series, “Cutie Honey” (1973), which is considered the first to feature a female protagonist and a model for the transforming magical girls of the megahit, “Sailor Moon” (1991). Around the same time he invented the “mecha” super robot genre with his series, “Mazinger Z” (1972), the first to show a giant mechanical robot piloted by a human character, and inspired, he says, by iconic ’60s robot manga “Astro Boy” (“Tetsuwan Atomu”) and “Gigantor” (“Tetsujin 28-go”).

But “Devilman” emanates from darker historical roots. Specifically, the Vietnam War. “There were many photos in the newspapers — most notably, the famous photo of the burned napalmed girl — I remember very well,” says Nagai. “If ordinary people didn’t go to war, I thought, they could be very nice people. So what happens to humans when you take away the framework of laws and put a weapon in their hands?”

Netflix’s Tokyo-based director of anime, Taito Okiura, says that the streaming platform’s liberties enable artists like Nagai and Yuasa to explore the darkest regions of the human character, giving them the freedom of feature filmmakers, but in the episodic format of anime.

The site’s other big title of 2018 was the equally unexpected “Aggretsuko” (“Aguresshibu Retsuko”), a darkly comic musical melodrama about a frustrated corporate drone (“office lady” or “OL”), personified by a female red panda who shrieks the lyrics to death-metal karaoke songs for stress relief. The character was created by Sanrio Co. Ltd., but she’s a far cry from the company’s famous feline Hello Kitty.

“Aggretsuko” garnered significant attention in overseas media when it debuted this spring, even warranting mention in Vogue magazine. “It resonated particularly well with global female millennial generations,” says Okiura. “We were surprised that many of our non-Japanese female colleagues fell in love with the character, saying, ‘It’s me!'”

While Netflix is mum on the future of “Devilman Crybaby,” Nagai has created a spinoff manga series for older readers called “Devilman Saga,” and Yuasa tells me that he’d jump at the chance to direct a second season. Netflix confirmed at this summer’s Anime Expo in LA that a new series of “Aggretsuko” episodes will launch next year, together with anime adaptations of live action titles such as “Pacific Rim” and “Altered Carbon,” and the long-running tokusatsu (special-effects) classic, “Ultraman.”

The company’s much-ballyhooed promise to produce 30 anime exclusives at the start of this year has generated some unlikely hits and the usual spate of forgettable misses. But Netflix is undaunted by the challenge. “We are very happy with the increasing number of our anime offerings from 2017 to 2018,” Okiura says, “and we intend to sustain this momentum.”

Roland Kelts is the author of “Japanamerica: How Japanese Pop Culture has Invaded the U.S.” and a writer in residence at the Catwalk Institute.