The method they employed to raise their spirit powers, was not fully understood even by they themselves, as people from the Middle Realm. They had been able to use it all this time, but only as an ability that they had been born with. And if you were to ask them to dissect this unique ability and explain the entire concept to someone, that was something that would be completely beyond them.
If the concept behind that ability was so easily understood, then the gap between the powers of the people between the Middle Realm and the Lower Realm would not be that huge!
Not to mention mere young youths just like Qiao Chu and his companions, to even find people from the Twelve Palaces themselves who really understood the ability fully was difficult as there were only a rare few, and the Twelve Palaces had been rather reluctant to use something like this as a lure for the Lower Realm people to risk their lives for them.
