“It’s human nature that we come in our own flavours,” fantasy author NK Jemisin tells the Guardian, “and it doesn’t make any sense to write a monochromatic or monocultural story, unless you’re doing something extremely small – a locked room-style story. But very few fantasy worlds ever do that. In fact, epic fantasy should not do that.”

Jemisin is on the phone from her not-very-epic day job as a university administrator in New York. When she gets off the phone, she says, she’s going to bike to a coffee shop to write her thousand words for the day, a pace that allows her to finish about a novel a year.

Her novels are anything but monochromatic. The first, titled The Killing Moon, is set in a multicultural sort-of alternate Egypt, where a patriarchal monarchy committed to order and peace, and a semi-egalitarian oligarchy, vie for power in a complicated web of shifting alliances and dreams. That story got her an agent, but didn’t sell initially – because, Jemisin says, “a fantasy novel set in something other than medieval Europe featuring an almost entirely black cast, is considered risky”.

Jemisin was undeterred. In 2010 she published her first novel, The Hundred Thousand Kingdoms, a sweeping story about a wide-ranging, heterogenous empire whose ruling family has enslaved the gods – at least for the moment. It was nominated for most of the major laurels in the industry: a Hugo, a Nebula and a World fantasy award.

The success of The Hundred Thousand Kingdoms and its sequels The Inheritance Trilogy enabled Jemisin to publish The Killing Moon and its follow-up in The Dreamblood Duology. Her next novel, The Fifth Season, comes out in early August. It’s an ambitious book, with a shifting point of view, and a protagonist whose full complexity doesn’t become apparent till toward the end of the novel.

Stereotypical fantasy series like, say, The Lord of the Rings, usually present a virtuous status quo threatened by a dark and eventually defeated outsider. But Jemisin’s stories almost always involve a flawed order, and the efforts (also flawed) to overthrow it. That’s certainly the case in The Fifth Season, where one character uses his magic to literally tear the earth apart rather than face enslavement again. “The goal is survival,” Jemisin writes in the novel, “and sometimes survival requires change.”

As a black woman I have no particular interest in maintaining the status quo. Why would I? NK Jemisin

“As a black woman,” Jemisin tells me, “I have no particular interest in maintaining the status quo. Why would I? The status quo is harmful, the status quo is significantly racist and sexist and a whole bunch of other things that I think need to change. With epic fantasy there is a tendency for it to be quintessentially conservative, in that its job is to restore what is perceived to be out of whack.”

She adds: “I think our society right now is enduring change in a painful and bloody way that is not necessarily a war.” She points to the incident at the McKinney pool in Texas, where police officers manhandled and arrested black teens at a white swimming pool. The white woman who started the incident by yelling racist slurs was quickly identified on Twitter, and lost her job as a teacher.

There’s danger in using Twitter to shame people, Jemisin said, “especially for women. You end up with threats and harassment and so forth.” But in a racist society, she believes, there are few other avenues for holding the woman accountable for traumatising and threatening the lives of black youth. “I see a revolution in that,” Jemisin added. “I see unorthodox change and I see it being effective. And that gives me additional material to possibly write with.”

Jemisin’s work itself is part of a slow but definite change in sci-fi and fantasy. She first got involved in fandom and writing through online forums. “I remember a few times going into bastions of the genre and just fleeing in horror,” she said. “For a while you would go into the Asimov forum and see people openly speculating about the humanity of black people, or women.”

Things are better in some ways, as Jemisin’s own successes demonstrate. But the progress has generated resistance. Earlier this year, a number of writers and sci-fi industry insiders began to organise and protest against the fact that nominees for the Hugo awards have become substantially less white and less male. The disgruntled have formed groups, calling themselves the Sad Puppies and the Rabid Puppies, and have reached out to Gamergate, the similarly reactionary movement protesting feminist criticism of video games.

The Puppies claim to be interested in returning to more entertaining, less ideological sci-fi, but their rhetoric can be startlingly racist. One of the leaders of the Puppies, a fantasy writer named Vox Day, referred to Jemisin in particular, and black people in general, as “half-savages”. (He has also argued that women should not be allowed to vote.) The Puppies managed to game the Hugo awards system this year, getting a slew of reactionary works on the ballot through coordinated voting for their own slate of adamantly less innovative science-fiction.

Jemisin is obviously no fan of the Puppies, but she sees a positive side effect from their crusade. “What I find heartening,” she said, “is the sheer amount of laughter the Puppies are engendering as they demand that what they call ‘affirmative action’ works no longer be considered, but really at the same time, they’re putting only their own friends on the ballot. So they’re actually asking for their form of affirmative action to replace what they think of as affirmative action. And everyone is realising it. People are looking at these authors [like Vox Day and Puppies leader Brad Torgerson], who they once took seriously, and now just pointing and laughing.”

Jemisin herself finds the traditional white male fantasy milieu somewhat laughable, or at least incongruous. “I hear all the excuses: things were just like that back then. There really were 90% men in medieval Europe and they were all white and somehow they magically got silk from East Asia and we don’t know how that happened, we’re not going to talk about that,” she said. “But that makes no sense to me. I don’t really understand why so many fantasy writers choose to focus on worlds that just seem strangely denuded. But to them I guess it doesn’t seem strange. And I guess that’s their privilege. It isn’t mine.”