The secret to breaking through to the Open Heaven Realm that could be exchanged for military achievements must be this.
As for Earth, Water, Fire, Wind, it's not about the secondary rules of these four main rules per se, but rather, any four secondary rules that embody the characteristics of Earth, Water, Fire, Wind.
This secret to the breakthrough into the Open Heaven Realm is actually just a paper-thin barrier.
Those who don't know and try to guess on their own will find it extremely difficult to do so, after all, how to verify it is a huge problem.
In the Emperor inheritances of the human race that Chen Fei has seen, there are numerous ideas about how to break through to the Open Heaven Realm, but in the end, none have the ability to prove whether these ideas are true or false.
To control one main rule and break through to the Open Heaven Realm, in the human race's inheritances, this conjecture is the most common, but it's almost certainly the least likely to succeed.
