About 800 years ago in Iceland, a poet named Snorri Sturluson put pen to parchment to record the already-millennia-old stories of a trickster deity from Norse mythology known as Loki.
Now it’s novelist Mackenzie Van Engelenhoven’s turn.
Van Engelenhoven — known to the fans of her popular young-adult novels as Mackenzi Lee — was thrilled when she was tapped recently by Marvel Comics to write a series of YA sagas about the franchise’s most sympathetic villains. The first will focus on Loki, who was borrowed from the Norse pantheon to become a staple of Marvel’s fictional universe in the 1960s. “It’s incredibly cool to be part of that legacy,” Van Engelenhoven said, “a work that has had so many creators in so many ways over time.”
In a way, she added, working with a legacy character takes her back to her roots. As a kid, she would write fanfiction, scrawling stories about characters from fantasy novels and sci-fi movies in a notebook.
“Fanfiction is so fundamentally a part of who I am as a writer,” she said.
She was curled in a chair in her living room in Jamaica Plain on a sunny weekday; as we talked, she kept getting upstaged by Mila, a glamorous white golden retriever who belongs to her roommate, Laura Koenig, who oversees children’s services at the Boston Public Library’s main branch. Ordinarily, at this hour Van Engelenhoven would be at her day job as events planner for Trident Booksellers and Cafe, but a fire had temporarily closed it down a few days before.
Van Engelenhoven has plenty to keep her busy: Along with the Loki book, she’s working on a sequel to her 2017 breakout, “The Gentleman’s Guide to Vice and Virtue’’; researching her next novel, which will be set during the tulip speculation frenzy of the 17th century; and preparing for a book tour to promote “Bygone Badass Broads,’’ a nonfiction book of short historical profiles released last month.
It’s a lot to handle, but she’s excited — especially about getting to meet her readers on the tour. “Teenagers come to you ready to love your books,” she said. “No one loves things the way teenagers love things.’’
As a kid growing up in Utah, Van Engelenhoven loved stories. Not necessarily books. Instead of reading, she and her sister preferred audiobooks. Her parents bought them each a boombox, and they would carry them around the house, listening to books on tape. (They didn’t use headphones, so they had to keep a little distance from each other while listening.)
Meanwhile, adults who thought of Van Engelenhoven as bookish would give her well-meaning classics — “Anne of Green Gables,’’ “A Little Princess,’’ “Little Women’’ — but she found them less than compelling.
“I don’t think I was a very good reader,” she says. “I would get handed these books and not be able to read them, and I would feel really dumb.”
When she did find a tale she loved, however, she loved it with her whole being.
For example: Shannon Hale’s fantasy novel “The Goose Girl,’’ based on the Grimm’s fairy tale. Hale was a Utah author, and Van Engelenhoven went to all of her book events wearing a blue cloak she’d made in a sewing class, so she could look like the main character.
“That book was so important to me,” she said. “That’s the book I would write fanfiction of, before I knew what fanfiction was.”
‘In the way of fanfic, I decided I was going to do my part to give these historical narratives back to people who’ve been excluded from them.’
Later, when she found online fanfiction communities where writers traded stories back and forth, they nurtured her confidence as a writer: “You get feedback immediately,” she said. “You have people who are cheering you on.”
In a way, fanfiction is nothing new: When Sturluson wrote down the Norse tales, he was writing characters that were well known to his readers.
Today, fanfiction also allows practitioners to make tales more inclusive. For example, on “Star Trek’’ Uhura typically had only a few lines per episode, but in the hands of various writers, she has become the main protagonist of several works. And while BBC’s “Sherlock’’ has only flirted with homoeroticism, many in fanfiction have already explored the complex relationship between its two leading men.
“So many women and queer people and minorities turn to fanfiction,” Van Engelenhoven said, “because you’re not seeing yourself in these [traditional] narratives, in these worlds you really love.”
As she got older, Van Engelenhoven’s affection for stories hit an obstacle. She felt as if she was too old for YA novels but didn’t find literary fiction as satisfying.
Instead, she stopped reading fiction and became a history major in college. By chance, around that time, she found a copy of “The Goose Girl’’ in a bookshop and reread it, remembering all over again why she loved it.
So after graduation, Van Engelenhoven went to Simmons to get an MFA in young-adult fiction. She began writing the story that would become her first novel: “This Monstrous Thing,’’ a “Frankenstein rehash” that was published in 2015.
Van Engelenhoven had gotten a two-book deal. Like many authors, she found the second book grueling. A first novel isn’t written under pressure, while a second one has already been paid for with an advance. “I just couldn’t make it work,” she recalled. “I was like, ‘Can I just give them the money back?’ ”
To blow off steam, she started writing another historical novel just for fun. This one would focus on a young British lord in the 18th century and embrace every hoary trope and plot device she loved. But “in the way of fanfic,” she said, “I decided I was going to do my part to give these historical narratives back to people who’ve been excluded from them.” The self-described ardent feminist made her protagonist a bisexual rogue and gave him a black love interest.
At first, she used the second, secret novel as a reward for working on her more artistically serious “official’’ book. But finally, she sent a draft to her agent, Rebecca Podes of the Rees Literary Agency, who wrote back: “This is what you need to be working on.”
That draft became “The Gentleman’s Guide to Vice and Virtue,’’ a New York Times bestseller, Kirkus Prize nominee, and Stonewall Honor award winner.
When her fans found out she was writing a book about Marvel’s Loki, they wanted to know whether, like her protagonist from “Gentleman’s Guide,’’ she would write Loki as queer.
Yes, she tweeted. “Loki is a canonically pansexual and gender fluid character.”
The announcement sparked a fierce online backlash from some who felt that Van Engelenhoven was forcing an interpretation on the character in a misguided nod to diversity.
She defended her position, noting that the character switched genders a few times in the pages of Marvel comics and that the Nordic myths refer to the character’s gender fluidity — including an episode wherein the god gives birth to a horse.
Getting the Marvel gig brought her back into the orbit of a personal hero: “Goose Girl’’ author Hale.
It turned out Hale had also written a YA book for Marvel, dealing with one of the most powerful of Marvel’s superheroes, “Squirrel Girl.’’ So Van Engelenhoven contacted her to get a sense for what working with Marvel was like.
Toward the end of the conversation, she mentioned, that she’d always been a big fan.
A few days later she got a message from Hale. “I have to ask you a weird question,” she said. “Did you used to wear a cape to my events?”
An earlier version of this story incorrectly stated the name and breed of Laura Koenig’s dog.S.I. Rosenbaum, a freelance writer based in Boston and New York, can be reached at email@example.com