Mind Reading was not without side effects, however.
Just as its description stated, it did not observe thoughts, but the other person's soul. Whether or not the target was touched, it would imprint the "contents" it read—that was, store souls. The only difference was the amount stored.
The problem was that these imprinted souls would mingle with the ability user's own soul, producing adverse effects in all sorts of ways, such as interfering with the circulation of a Mind Method.
These insights did not come from Luo Diya's experience. She knew almost nothing about souls.
They were Chen Xuan's conclusions, drawn from the knowledge he had learned from Liu Shuyue.
In a sense, it was rather like a Cultivator slaying Demons: absorbing a Demon's Spiritual Energy made the practitioner stronger, but also made their Spiritual Energy more impure.
The Lotus Cloud Sect had completely abandoned this method of cultivation, instead absorbing the Spiritual Energy of heaven and earth for their own use. The results came much more slowly, but outbreaks of the Heart Demon were greatly delayed, and the upper limit of cultivation was higher and safer.
Of course, with the Soul Forge now, there was an additional means of clearing out impure souls. But excessively fragmented soul pieces were still difficult to locate in their entirety.
As its user, Chen Xuan understood this with exceptional clarity. In that universe seemingly composed of countless scraps of souls, he needed an extremely clear goal in order to lock onto the corresponding soul and select it as forging material.
That was also why he had not chosen to keep Mind Reading on him at all times.
Luo Diya might not care about souls becoming mixed together, but he certainly did.
After all, there really was a Mind Method circulating within him.
Chen