Unless one is a fool, it's clear after hearing Gu Han's words that the Ancient Blood Tower possesses countless sect secrets and martial arts techniques. Moreover, those sect members who grew with the assistance of exchanges through the Blood Tower have become its greatest supporters, as there has never been a shortage of traitors in this world.
Since Xu Sheng engraved the "Spiritual Power Analysis" on the stele of Tian Nan, any martial arts techniques below the Earth Level no longer held any secrets, even the mystical arts and divine abilities could be deduced using the method of spiritual power analysis if one understood the way of cultivation. The encryption used by sects could only prevent outsiders, not the insiders.
The cleverest thing about the Ancient Blood Tower was that it operated under the guise of exchange. In other words, with every transaction, the Ancient Blood Tower could obtain two sets of secret techniques, while the two traitorous disciples would each gain one.
