Kotaku's sources say the presentation was supposed to end with a video featuring Blizzard co-founder Allen Adham solidifying plans for a Diablo 4 while assuaging fans wanting to see footage. According to sources who spoke to Kotaku, Blizzard had meant to tease Diablo IV, which is indeed in development, but decided at the last minute they weren't yet ready to commit.
In a note to investors, research firm Cowen & Company said "Blizzard severely miscalculated how their fans would respond, which suggests they aren't in touch with their players as maybe they should be".
Hopefully, Blizzard will soon announce Diablo 4 as well but until then, we can look forward to other titles announced at the BlizzCon 2018, including the Warcraft 3: Reforged.More news: MTV European Music Awards round up - CBBC Newsround
However, that video was pulled in the last few weeks, possibly due to instability on the Diablo team.
Despite asking fans to reel in their expectations for Diablo-related news at BlizzCon 2018, it turns out the company had plans to tease the development of Diablo 4 anyway. However, according to two anonymous insiders who spoke to Kotaku, Blizzard originally planned on closing with an announcement for Diablo 4, but cut it from the opening ceremony at the eleventh hour. Blizzard Entertainment's sole Diablo announcement at the convention, revealing the mobile game Diablo Immortal, was met with vocal ire by portions of its fanbase, partially because the game simply wasn't the true sequel that fans had been hoping for - and, fans assumed, had been teased for months.
Those familiar with the situation said the Diablo team wasn't ready to commit to an announcement, since Diablo 4 has changed immensely over the past four years.More news: Christian pilgrims' killers are slain in shootout, Egypt says
In August, Diablo Associate Community Manager, Brandy Camel, said they had numerous Diablo projects that were being worked on.
Diablo III launched in May 2012, and its first and only expansion, Reaper of Souls, followed in March 2014.
IGN has reached out to Blizzard for comment and will update this story as such.More news: Samsung foldable phone teaser previews some big news