EUREKA: I think I find out how an Act 2 merc's aura is turned on I'm talking about Act 2 Aura mercs. In the past, someone asked about how the merc decided to turned on his auras, such as Prayer, Might, Holy Freeze, etc. Obviously, the aura is not on at the beginning of the game. I have a lvl 86 Might Merc. I spent several nights on studying his behavior and here's my report. FINAL CONCLUSION: The mercenary's aura is turned on if and only if he loses health. I'm not 100% sure about this conclusion, but I'm sure the merc's aura cannot be turned by the following factors: 1) The character loses health 2) The character dies 3) The minions (Revive, skeleton, mage, Golem) lose health 4) The minions die 5) Anyone in the party does damage 6) The merc is hit but doesn't lose health When the game begins, the merc's health is always full. So the aura is off. In some games, the merc's aura is not turned on for a long time. It might be caused by: 1) The merc's high defense. Attack by the enemy is blocked 2) The Act 2 merc's Jab skill. I found out the jab skill hit pretty fast so the monster didn't fight back at all. 3) Your minions distract the monsters so that the merc isn't attacked. The experts in this forum may want to test this hypothesis on other Act 2 mercs. All feedbacks are welcome and appreciated. If you have already noticed this effect, try not to laugh.