In an anxiously anticipated new story, "Harry Potter" author J.K. Rowling has transported her world of magical wizarding across the Atlantic — and some Native American commentators are not happy with the result, saying it exploits and distorts Native culture.

Rowling posted the first part of the four-part series "The History of Magic in North America" to her Pottermore website Tuesday afternoon. The mock-academic collection, published over four days, promises to "enlighten readers about a previously unexplored corner of the wizarding world, taking us into the lives of North American witches and wizards, their history and their magic, and introduces audiences to a new era of the world that J.K. Rowling has created," according to Pottermore's publicity rollout.

But the magical world depicted in the first story, "Fourteenth Century — Seventeenth Century," isn't purely drawn from Rowling's imagination. One passage references the Navajo legend of the "skin walker":

"The legend of the Native American 'skin walker' — an evil witch or wizard that can transform into an animal at will — has its basis in fact. A legend grew up around the Native American Animagi that they had sacrificed close family members to gain their powers of transformation. In fact, the majority of Animagi assumed animal forms to escape persecution or to hunt for the tribe."

Adrienne Keene, a Cherokee writer who created the Native Appropriations online forum, wrote in a blog post Tuesday that Rowling's take recklessly misrepresents a tradition that still has very real meaning to many.

The belief in skin walkers "has a deep and powerful place in Navajo understandings of the world," Keene wrote. "It is connected to many other concepts and many other ceremonial understandings and lifeways. It is not just a scary story." (You can read her full post here.)

But that history and nuance could be eclipsed by Rowling's take, Keene said. "Rowling is completely re-writing these traditions. Traditions that come from a particular context, place, understanding, and truth. These things are not 'misunderstood wizards.' Not by any stretch of the imagination."

Keene also took her objections to Twitter, where Rowling has been responding to fans with questions about the various minutiae of wizard history. In a reply to one Twitter user, who wanted to know if skin walkers were good or bad, Rowling wrote that the legend was fabricated by people without magic:

Keene jumped in with her own sharp reply:

Keene was not alone. Other Native people took to Twitter to voice their disappointment and demand a response from Rowling, who has not answered her detractors online. A Pottermore spokesperson declined to comment for this story.

Navajo writer Brian Young tweeted that Rowling's depiction of Native culture left him "broken-hearted."

Some Native American fans also objected to Rowling's use of the phrase "the Native American community" — there are hundreds of different Native American tribes, each with their own culture and traditions — as well as references to certain stereotypes: Rowling writes that the Native American wizards were "particularly gifted in animal and plant magic"; the trailer for the series  features a Native man in a loincloth leaps from a cliff and turns into an eagle.

Johnnie Jae, founder of the radio show and website A Tribe Called Geek, bemoaned that Rowling would likely be applauded for including Native culture in her fictional history — rather than questioned for the way that culture was portrayed.

Sure enough, several Potter fans came to Rowling's defense on Twitter, arguing that she intended to honor Native culture, that the story is "just fiction" and that her critics were being oversensitive.

But the mass appeal of Harry Potter is exactly why Native voices needed to speak up, Keene wrote.

"As I often say, when you're invisible, every representation matters," she said. "And the weight and impact of the Harry Potter brand can't be ignored."