The reason is not hard to understand. The Military Town is only responsible for High-Turn Messengers and can afford to spend a lot of time and even casualties to attack the Secret Realm because High-Turn Messengers only care about the Clear Treasure Chest. However, Demonic Messengers are responsible for themselves, so naturally, they only do what they are capable of. Moreover, most Demonic Messengers are bullies who prey on the weak; how could they possibly risk challenging powerful demon fiends?
Since no one is willing to clear the Secret Realm, it is better to reset it multiple times. Everyone can fight the Shadow Wolf several times, at least gaining more rewards.
