It’s the end of the Chilton era for World of Warcraft.

After a decade of overseeing one of the biggest games ever made, World of Warcraft director Tom Chilton is leaving. The designer announced in a blog today that he is stepping down from the lead role on Blizzard’s massively multiplayer online role-playing game now that Legion, the latest (and greatest) expansion has launched. But Chilton isn’t done at Blizzard. He revealed that he is sticking with the company and is now working on something new. The director worked on Warcraft since 2004, and he was key to turning it into one of the most popular and lucrative hits in the history of the $99.6 billion gaming industry.

“It’s with a mix of excitement, sadness, and gratitude that I’m saying farewell to the WOW team and moving on to a new adventure within Blizzard,” Chilton wrote in a message on the Blizzard forums. “My personal journey working on WOW as Game Director is at an end, but my journey with Blizzard isn’t. I’ll still be here, but will be focusing on another project within the company.”

Chilton also announced that Ion Hazzikostas, lead game designer on World of Warcraft, will take over as director. Hazzikostas has worked on WOW for eight years, and he is responsible for many of the raid bosses and other major encounters.

“I know that WOW will be in great hands with Ion at the helm,” wrote Chilton. “He’s been an integral part of the team for more than eight years and has contributed to so many aspects of the game’s development — from class design to encounter design and nearly everything in between. He also has an amazing team at his side — the same epic crew that brought you all the content you’re enjoying in Legion.”

World of Warcraft was long Blizzard’s crown jewel, but it is entering the twilight of its life. It peaked in 2010 with 12 million subscribers, and it has since dwindled to less than half of that — although the publisher no longer releases the figures for how many people pay for a monthly membership. WOW still generates millions of dollars in revenue every month, but fans have still wondered whether Blizzard would replace it with something new. The studio was working on a new MMO called Titan, but it eventually canceled that project and repurposed many of the assets and ideas for the popular Overwatch shooter that launched in April.

The publisher now has several active, profitable games in WOW, the card battler Hearthstone: Heroes of Warcraft, Diablo III, StarCraft II, and Overwatch. And it doesn’t seem like it wants to try to do another MMO. At the same time, Chilton is working on something new, so we’ll get to see how that manifests over the next few years.

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