HBO Max is reportedly developing a brand-new Hogwarts Founders series, and if the casting rumors are even half true, fans are in for something special. The names being thrown around? Henry Cavill as Godric Gryffindor and Tom Hiddleston as Salazar Slytherin. A series diving into the origins of Hogwarts, ancient magic, rivalries, and legends, with a cast like that? Yes. Please. Nothing confirmed yet… but wizarding fans are already dreaming.

The rumor exploded across social media in early 2026, with Instagram posts, Threads threads, and Reddit discussions lighting up timelines and forums. Posts from accounts like @letstalkmovies.co and @dazzling_chisom described the potential project as a deep dive into the founding era of Hogwarts School of Witchcraft and Wizardry, centuries before Harry Potter’s time. The four founders—Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff—built the castle together in the 10th century, each contributing unique magical philosophies that shaped the four houses. Their alliance fractured over time, most dramatically when Slytherin’s pure-blood supremacist views clashed with the others’ inclusivity, leading him to leave and create the Chamber of Secrets. A series exploring this era promises epic scope: medieval wizarding society, forbidden spells, mythical creatures, political intrigue, and the birth of the house system that still defines the Wizarding World.

While HBO’s flagship Harry Potter TV series—adapting J.K. Rowling’s seven books with a new cast, including Dominic McLaughlin as Harry and Paapa Essiedu as Severus Snape—is firmly in production at Leavesden Studios and slated for a 2027 premiere on HBO and Max, no official word has emerged about a separate founders prequel. The main series focuses on a faithful, season-per-book adaptation, with showrunner Francesca Gardiner and director Mark Mylod steering a decade-long commitment. Yet fan speculation has spun the founders idea into viral frenzy, fueled by the franchise’s massive untapped lore and the allure of seeing its origins on screen.

The casting rumors are particularly intoxicating. Henry Cavill as Godric Gryffindor feels almost predestined. The British actor, renowned for his portrayal of Superman, Geralt of Rivia in The Witcher, and his upcoming roles in Highlander and Voltron, embodies the chivalrous, courageous warrior archetype. Gryffindor, described in canon as “bold, daring, and chivalrous,” valued bravery above all. Cavill’s physical presence—towering stature, commanding voice, and ability to convey both fierce determination and quiet nobility—makes him a dream fit. Fans point to his sword-fighting prowess (honed for The Witcher and Highlander) as perfect for depicting Gryffindor’s legendary duels and his role in shaping knightly wizard traditions.

Tom Hiddleston as Salazar Slytherin is equally electrifying. Hiddleston’s Loki in the Marvel Cinematic Universe showcased his talent for portraying complex, charismatic anti-heroes—charming on the surface, cunning and ambitious beneath. Slytherin, the most controversial founder, prized ambition, cunning, and resourcefulness, but his legacy is tainted by prejudice. Hiddleston could bring nuance to the character: not a cartoonish villain, but a brilliant, idealistic wizard whose growing extremism fractures the group. His Shakespearean training and ability to layer menace with vulnerability would elevate Slytherin from historical footnote to tragic figure.

The rumored pairing promises fireworks. Cavill and Hiddleston—both British heavyweights with massive fanbases—could deliver a central rivalry that anchors the series. Imagine tense council scenes in the nascent castle, philosophical debates over Muggle-born students, and climactic confrontations as alliances shatter. Their on-screen chemistry (or tension) would be must-watch television.

Beyond the leads, fans dream of a full ensemble. Helena Bonham Carter or Olivia Colman as Rowena Ravenclaw, the wise and witty intellectual founder? Idris Elba or Djimon Hounsou as Helga Hufflepuff’s counterpart? (Helga’s warm, loyal nature could suit a grounded, empathetic performer.) Younger versions of the founders could explore their backstories—perhaps flashbacks to their own magical awakenings in a world where wizarding communities were scattered and persecuted.

The series could delve into rich, unexplored territory: the construction of Hogwarts itself (enchanted by the founders’ combined magic), early goblin relations, the origins of house-elves, the creation of the Sorting Hat (forged by all four), and the first Quidditch matches. Ancient magic—pre-Statute of Secrecy, when wizards openly wielded power—offers endless possibilities: dragon-riding, elemental spells, forbidden artifacts, and the birth of dark arts that Slytherin would later champion.

HBO’s track record with prestige fantasy (Game of Thrones, House of the Dragon) suggests they could deliver high production values: sweeping Scottish landscapes for the Highlands setting, intricate practical sets for the evolving castle, and VFX for magical battles that rival the films. A mature tone—exploring prejudice, power, betrayal, and legacy—would fit HBO’s brand, appealing to adult fans while honoring the source material.

The timing feels ripe. The main Harry Potter series will reintroduce the world to a new generation, potentially setting up spin-offs. A founders series could run parallel or follow as a prequel anthology, expanding the Wizarding World without retreading familiar ground. J.K. Rowling remains involved as executive producer on the main series; her input on expanded lore would be crucial.

Of course, these are rumors—born from social media speculation rather than official announcements. Many posts label them as “fan dreams” or “trust me bro” territory. Reddit threads dismiss them as bot-driven hype, and reliable outlets like Deadline and Variety focus solely on the 2027 main series. Yet the excitement is undeniable. Fans crave more depth in the Wizarding World, and the founders era—rich with myth and conflict—offers exactly that.

If HBO pursues this, Cavill and Hiddleston would be a casting coup. Their star power could draw massive viewership, while their performances might redefine iconic characters. Until confirmation comes, wizarding fans will keep dreaming—of swords clashing in candlelit halls, of ancient spells lighting up the night, and of two titans of screen facing off as the founders whose choices still echo through Hogwarts’ walls.

The castle was built on dreams. Perhaps this series will be too.