Armed with the Beheading Demon Catalogue, for Feng Yi, the Western Wilderness, being a Demon Tribe territory, was the perfect place for his cultivation.
He could not achieve the power to slay a demon saint like himself.
Therefore, even with the Beheading Demon Catalogue, to reach the peak of the Cave Heaven Realm Ninth Heaven, he would inevitably undergo great hardship.
After all, from the process just now, relying solely on the effects of the Beheading Demon Catalogue, to progress his cultivation from zero to one hundred in the Cave Heaven Realm Ninth Heaven, he would need to slay fifty of the Demon Tribe at the Cave Heaven Realm First Layer.
Not to mention the previous eight realms.
Moreover, the Cave Heaven Realm was not a common cabbage, such a large number of killings would inevitably lead to intense conflicts.
Thinking of this, Jiang Yuan slowly smiled.
He was even more satisfied with the improvements gained from slaying the demons now.
