While players are expecting Blizzard to reveal Diablo 4 at BlizzCon later this season, confirmation of its existence may have already leaked ahead of the show. An ad in Germany's GameStar magazine intended for newsstands on October 23 features a full-page advertisement for a new Diablo art book.
The text of the ad promises "over 500 artworks from Diablo, Diablo II, Diablo III and Diablo IV" and is due to go on sale in November. Blizzard's annual fan convention, BlizzCon, is scheduled for the weekend of November 1, so the timeline mostly checks out, though this magazine would be in stores sooner than a BlizzCon reveal -- if that's when we're to expect the rumored unveiling. The ad is already online now due to GameStar digital subscribers spotting it and sharing it online.
Attendees at BlizzCon last year also got their hopes up for a new Diablo reveal, but were largely disappointed when that reveal came in the form of Diablo Immortal, a new take on the action-RPG designed from the ground up for mobile devices. This year, it seems Blizzard may bring players the reveal they've been waiting for, but now that otherwise good news feels shrouded in different controversy following the publisher's move to suspend esports player blitzchung following his pro-Hong Kong comments during the Hearthstone Grandmaster Tournament on October 8.
The suddenly under fire publisher has since cancelled two events, one in Taiwan and another in New York, that were meant to celebrate World of Warcraft and Overwatch respectively. BlizzCon 2019 thus comes at an interesting time for the company, which is being boycotted by some and criticized by many. It seems unlikely, at least at the time of writing, they would cancel their convention this year, though at least one outlet, the crowdfunded Easy Allies, has already floated the idea of ignoring their announcements anyway.