How to effectively use quick battles (autobattles)?

2Dirty Player: It's not entirely clear about the Cerberuses, but it seems that in quick battles, they are the same as Hydras, but with fewer hit points. They are feared because the retaliation will come from all of them. Each of the three Archdevils is afraid, and as a result, none of them attack until they die. By the way, the same thing happens when capturing a Hive: the flies don't even fly away.