I went ahead and trained up the cooperation tree the other day and go the demons. They were super powerful and became my only unit in the game. I was able to use their special ability on each turn in combat and wipe out entire armies without ever having to move my demons. Today I started a new game but this time the demons can only use that ability once during a battle. Is this normal? Is there something that allows them to use their ability on each turn during a battle?