The should just make DE an Aura on the pets that lasts for 12 seconds. So when a new pet comes into range of one when DE was cast it gets the buff for how ever much is left. It means we still have to watch it if the position of imps change for the fight but most will still get it under normal circumstances but we still have to watch it for upkeep. We still need to cast it every 12 seconds but not after ever demon summon.