Like Sabrina Spellman (Kiernan Shipka), the protagonist of Netflix’s Chilling Adventures of Sabrina, production designer Lisa Soper was born on Halloween. “I know,” she said in an interview Monday, a few days after the series debuted. “There were so many random coincidences with this show.”

The other coincidence: Soper, like Sabrina, is a practitioner of the occult. Sabrina’s witchcraft is a fictional blend of magic and mysticism drawing from a variety of subcultures; paganism, which Soper practices, is one of them. Her beliefs made designing this show—helping show-runner Roberto Aguirre-Sacasa conceptualize the magical framework around each episode’s action—a professional challenge with deeply personal resonance.

Contemporary paganism, sometimes referred to as modern or neo-paganism, is an umbrella term for belief and practice that encompasses modern witchcraft, including Wicca. The Church of Night in Sabrina is a fictional construct (we . . . hope), but witches aren’t. According to the Pew Research Center, about 734,000 Americans identify as Wiccan or pagan. The Economist estimates that over 100,000 Britons likely practice neo-paganism; in Iceland, Nordic paganism is the nation’s fastest-growing religion.

Soper helped to create the sets of Chilling Adventures of Sabrina, building structures that echoed the magical elements of the story—particularly the Spellman house, which is loaded with symbolic details and charmed touches. Viking runes for resurrection and death are carved into the entryway. The foyer is symmetrical, reflecting Sabrina’s emphasis on balance, and the opposing poles of gender, morality, and mortality. A calming sigil—one Soper draws into the ground when she walks in the woods during her own pagan practice—appears on the floor of the Spellman house. Even the walls are all deliberately askew.

Once the set was constructed, Soper added, “I put a protection spell on the house. I didn’t have to hide it.” The rest of the crew has been careful not to disturb any of the artifacts in the house, lest they disrupt the magic of that spell. Soper’s ritual, she said, incorporated a sacred circle, burning sage, as well as “different salts and crystals that are laid out as charms and protections.”

Soper also drew on her own knowledge while designing the look and feel of the spells incanted on-screen by Sabrina and her fellow practitioners of magic. For those, Soper consulted her personal collection of spell books and religious histories—such as The Lesser Key of Solomon, which is believed to be the oldest grimoire—looking for the closest approximation to what the show required: “What’s the closest thing they did, if they even tried to do these types of things? What we do is, we take from the same tones . . . what’s the driving force of trying to pull this kind of power?”

The idea was to build a magical framework that draws from traditions around the world. The demon Apophis, for example—whom Sabrina and her friends encounter midseason—is drawn from ancient Egyptian lore. “The only depictions of him are this giant snake-worm-like creature consuming a man,” Soper said. “The tablet in the cave”—the one Sabrina uses to identify the demon—“is the original iconography.”

“We’re pulling from Egyptian stuff, and different Middle Eastern realms—trying to go as old as possible. The newest stuff is the Salem witch trials era,” she explained—the infamous persecution that led to the hanging of 19 suspected witches between 1692 and 1693. (A few writers on the show are also practitioners of paganism; one even lives in Salem.) The Greendale mine, which is so important to Harvey Kinkle (Ross Lynch)’s witch-hunting family on the show, has a marker indicating it was founded during the trials, linking that historical event with the drama of the Spellman family—and injecting a bit of horror into the threat posed by the Kinkle family, headed by Michael Hogan.