Die-hard Harry Potter fans have always been loyal to their wizard wunderkind, but they weren’t exactly known to be food activists — until now.

This week, Harry’s devotees announced that they had succeeded in their four-year battle to get Warner Bros. Entertainment to use only fair-trade certified chocolate in its branded candy. This includes the chocolate frogs that were made famous in the books and sold at Universal Orlando's theme park, as well as Shock-O-Choc and HoneyDukes Chocolate Bars.

Since 2010, the Harry Potter Alliance (HPA), a social-justice group, has pushed for certification of the chocolate to ensure its production does not rely on child labor and that its producers are paid a decent wage. HPA founder Andrew Slack and his allies — including Harry Potter’s creator, J.K. Rowling — petitioned Warner Bros., which owns all rights to Potter products and merchandise, saying Harry’s fans didn’t think the fictional wizard would approve of unethically produced chocolate. 

When the very audience a company depends on speaks out for, or against, something, it's important for that company to listen-- or they risk losing important followers

- Ricky Brigante, Inside the Magic

“If ‘Harry Potter’ [as a franchise] were to be in alignment with the values of Harry Potter [himself], it could be a real symbolic and coherent victory,” Slack said.

On Dec. 22, Joshua Berger, president of Harry Potter Global Franchise Development, wrote to Slack announcing Warner Bros.' decision to use only certified fair-trade chocolate products. By the end of this year, the chocolate must be certified fair-trade or get approval from UTZ, a program and a label that focuses on sustainability and working conditions.

Candy, particularly chocolate frogs, plays an important role in the Harry Potter series. But in the real world, cocoa doesn’t just magically appear out of nowhere.

The group charged that Behr’s Chocolate, the company Warner Bros. used to make all Harry Potter chocolate, had a poor record on human rights and child labor.

After thousands of Harry Potter fans sent video complaints and letters, in 2013 the campaign teamed up with the global anti-slavery movement Walk Free to pressure Warner Bros.  In 2014, J.K. Rowling lent her support, and shortly after the HPA and Walk Free met with Warner Bros. executives, where they presented 400,000 signatures backing their campaign.

The win was a big one not only for the HPA, but also for Warner Bros., because fans are critical to a brand’s success — particularly one like Harry Potter, which encompasses books, movies, consumer goods and theme parks.

“When the very audience a company depends on speaks out for or against something, it's important for that company to listen, or they risk losing important followers,” Ricky Brigante, theme park expert of Inside the Magic, told FoxNews.com. “There's no doubt the brand continues to be as popular as it is thanks to its hardcore fans worldwide.”

But Jennifer Earle, a chocolate expert who runs confectionery tours through London, thinks chocolate makers are simply facing more pressure than ever to create an “ethical” product.

“I lead hundreds of people on chocolate tours, and on every tour someone asks me about ‘fair-trade,’” Earle said. “Big businesses especially want to be seen as doing good, as having a ‘likable personality,’ because they face greater competition from smaller businesses who often do have a face and personality behind their brand.”

Having the fair-trade stamp has become a big marketing tactic for many brands, Earle said. She also noted that fair-trade cocoa beans are not significantly more expensive than regular cocoa beans right now.

So fans clearly can have an impact when their wishes align with company goals. But when they don’t …

In the late 1990s, there was an enormous uproar from Disney fans after it was announced that Mr. Toad’s Wild Ride, a ride based on the book The Wind in the Willows, would be closing at Disney World’s Magic Kingdom in Orlando (the ride at Disneyland remains open). Thousands of letters were sent, t-shirts were made and avid enthusiasts even staged “Toad In’s” at the site of the ride. But despite the loyal following, Disney closed the ride in 1998.

More recently, Disney faced a backlash when it was announced that Disney World’s Maelstrom — a Nordic-themed adventure — would be replaced by a splashier “Frozen” attraction. But those efforts failed, and Maelstrom was closed last fall.

Still, there is plenty of hope for fans seeking to make a change. “Social media has no doubt given a powerful voice to fans,” Brigante said, citing a recent example when Disneyland threatened to end its long-running Aladdin show and install a Toy Story musical. Fans begged Disney to reconsider, and Mickey had a change of heart, letting the Aladdin show remain on stage.

Now superfans have etched another notch in their activist gun barrel. Fair-trade chocolate. Sweet.