Blizzard has opened a teaser site for something called 'Reaper of Souls', thought to be the first expansion pack for Diablo 3.
The site quotes Diablo 3's companion book 'Book of Tyrael', and features an image of a large, open doorway.
"Death, at last, shall spread its wings over all," reads the quote. Given the proximity to Gamescom, a full reveal during next week's show seems likely.
Diablo 3 launched on PC and Mac in May 2012, with a console version due to release on September 3. A PlayStation 4 release will follow next year.