Can I play Warhammer 40,000: Dawn of War III's single-player campaign offline?
It is recommended, but not required, that you have a stable internet connection while playing Warhammer 40,000: Dawn of War III's single-player campaign. You can play through the campaign while offline, but you will not earn Skulls (Dawn Of War III's in-game currency) or experience for your Elite units.
If you are playing Dawn of War III's single-player campaign online and lose your connection, you will still earn Skulls and Elite experience if you are able to reconnect to the internet within 90 seconds. If you lose your connection for longer than 90 seconds, you will not earn Skulls or Experience for the duration of your time offline.