"The first thing I'll tell you all is that The Cathedral is no more. Their members have been slaughtered and their rules have been abolished. Anyone found practicing their teachings will be killed without question."
Dyon didn't want anyone to find out that Soul Rend Quadrant was undergoing reform, or else their enemies might once more train their eyes here.
After Dyon's soul was unsealed, he was able to feel the sheer amount of soul energy filling this quadrant, so he immediately understood many things.
The soul talents of this quadrant were on a completely other level. If it had been allowed to continue existing, it would have been impossible to continue enforcing the separation of alchemy and formation theory. As such, it was destroyed.
Dyon couldn't just build it up again, or else he would just be asking for it to collapse once more.