Warlock – “Cultist” [Campaign 4, Mission 3]

To make demons appear in version 1.6, you need to install the bug fix. With the bug fix, the first demon will go to the first captured town, not the second, as in versions 1.0-1.5.

http://forums.ag.ru/?board=heroes5&action=display&s=0&num=1192719850&start=125 (post 146) - the bug fix.