Waiting for Reinforcements Diablo III Guide
Last update: 11 May 2016
You may encounter Captain Haile while exploring the Stonefort. He'll ask you for assistance in defending against enemy attacks until reinforcements arrive.
Survive the demon ambush
The monsters should appear near a hole in the middle of the stronghold wall. Continue fighting until they're all gone.
An elevator will soon arrive here, however instead of receiving reinforcements you'll discover that you'll have to defeat one more group of monsters. Winning this second battle will end the event and you'll be allowed to continue the main quest.