CORRECTION: Blizzard has confirmed that although it had a video made to announce a new Diablo game, it did not intend to release it at Blizzcon. The below article has been updated accordingly.
Diablo 4 has apparently had a reveal video created by Blizzard, but the company felt it was not ready for a reveal at BlizzCon 2018. Blizzard's work on another Diablo sequel has become one of gaming's worst-kept secrets, with the developer all-but confirming it when advising that it was working on multiple Diablo projects, but an official Diablo 4 announcement has yet to arrive.
That left Blizzard in an awkward situation at BlizzCon, with the only Diablo reveal being that of mobile-only game Diablo Immortal. This went on to receive a huge amount of negative feedback, in part due to dissatisfaction over a move to mobile gaming as a whole but equally because of a lack of official announcement of Diablo 4. In short, many PC-centric players felt as though the Diablo franchise was being moved out of its traditional home.
However, it turns out that Blizzard may have been able to dampen the negative response to Diablo Immortal if it had actually shared this reveal of Diablo 4. As revealed by Kotaku, the developer has an announcement video for Diablo 4 ready, but did not want to show it at the event. According to people close to Blizzard's plans for the event, a video confirming the development of Diablo 4 has been made, but due to the changes the project has seen since development started there is a hesitancy to announce it officially.
Instead, fans were left with the sour note of Diablo Immortal as Blizzard's big Diablo news from BlizzCon as a whole. The end result has been a wave of extremely damning criticism from fans, something that has perhaps been made even worse by Blizzard's decision to delete negative comments from the videos of Diablo Immortal's trailers.
The fact that some of this backlash could have been avoided will no doubt be frustrating for those involved. Although Diablo 4 is apparently not in a state where it is ready to be shared, simple confirmation that the game exists would have been enough to give some fans peace of mind. An example of this in action would be the reveal of The Elder Scrolls VI by Bethesda at E3 2018, which itself received a brief announcement alongside a more comprehensive overview of mobile RPG The Elder Scrolls: Blades.
All in all, then, this seems to be a series of errors from Blizzard, resulting in a serious amount of damage limitation being required. Even though this gives Diablo fans the news they have been hoping for - that Diablo 4 is definitely on the way - it's unlikely to take away the anger felt by many within the franchise's community. Perhaps when Diablo 4 is officially announced, the furore around Diablo Immortal will start to leave the memory.