Michael Chu's first credit at Blizzard, according to MobyGames, is as a tester on Diablo 2: Lord of Destruction, all the way back in 2001. And unless he returns, it appears that his last will be as lead writer on Overwatch, as he announced today that after 20 years at the company, he's moving on to other things.

"When I first walked through the doors of Blizzard Entertainment 20 years ago, my only dream was to help make the games I had spent countless hours of my life playing. From the battles between the races of Azeroth in Warcraft to the corruption of humanity as pawns of the Eternal Conflict in Diablo, I was lucky enough to tell stories in these amazing universes and help bring them to life. And I have had the great fortune to get to know and interact with the passionate global community that played our games," Chu wrote in a farewell message on his blog.

Chu also worked as a writer and world designer on Diablo 3 and World of Warcraft, but Overwatch is where he made his biggest splash: He was responsible for much of the Overwatch lore and origin stories that established the game's characters as individuals rather than merely classes with surnames.

"We have all these individual characters, we have these great stories, challenges, powers and stuff, and they all have their own little ecology," he said in a 2015 interview, discussing Blizzard's approach to the Overwatch narrative. "But then when you mix them all together, they start to have relationships. They start to tackle larger worldview problems. And I think that's kind of where that inspiration leads."

Twenty years after first walking through the doors at Blizzard, I’m moving on to new adventures! Overwatch has been an amazing experience and one that I will treasure forever. Thank you to everyone for your support over the years! https://t.co/rG4zPe9SGCMarch 11, 2020

"Overwatch offered an opportunity to bring a more inclusive vision of Earth to life: a future worth fighting for," Chu wrote on his blog. "Together, we worked, struggled, and shed tears to champion a universe that featured people from across the world, to bring to life the wondrous sights of earth’s past, present, and future, and to empower the contributions of creators and voices who would better represent the breadth of human experience. I believed that a game could show the power of diversity and that one kiss could change the world, if only a little."

Chu didn't reveal what his future plans are, except that he hopes "to continue to tell these stories and build worlds that unite people through games." The bigger question, from the perspective of Overwatch fans at least, is how his departure will impact Overwatch 2. While Overwatch is a multiplayer shooter—which, deep backstory notwithstanding, makes the story bits optional—Overwatch 2 is going all-in on PvE missions, with Story and Hero missions that will tell the tale of a new battle against Null Sector.

We said when the beefy Overwatch 2 cinematic was released at BlizzCon 2019 that "it feels different from the disjointed hero cinematics that we've gotten used to over the years, tying together multiple characters into a focused story." That's a complicated task that's not likely going to get any easier with Chu's departure.

Update: Following Chu's announcement, Blizzard released the following statement:

"We’re incredibly grateful to Michael for his contributions, and his presence at Blizzard will be missed. We’re not anticipating an impact to our plans for Overwatch 2. The game’s development is a massive collaborative effort involving talented people across multiple teams, all with a shared commitment to the values of Overwatch and the vision for Overwatch 2. We’re working hard to create an epic, story-driven experience for players, and we can’t wait to share more."