The book's third section was an addendum to the second, examining the nature of Horcrux magic through the phenomenon known as "Death Force." After forcing himself to read through the section despite his discomfort, Avada finally understood why Professor Baker had said he "didn't need to use such an evil method to make a Horcrux."
The so-called "splitting of the soul through murder" was actually a matter of borrowing the Death Force generated at the moment a victim died. As it drew out the victim's soul, it also tore off a piece of the killer's own soul. Because the killer's main soul remained protected by their mental and life forces, the fragment that had been torn away was not drawn off by the Death Force, but remained in the world.
An analysis of the structure of mental force showed that, during a "malicious murder," the killer's mental force happened to meet certain conditions. This made the part of it beside the soul's core extremely weak, allowing another force of Death to tear the soul apart, provided it was close enough. This was why the original form of Horcrux creation required the murderer to kill with malice—and why it had become infamous as the most evil of magics.
Once the principle was understood, it was possible to bypass the restriction of "malice" simply by designing a different meditation method. Even the requirement of "killing" could be bypassed. In theory, someone could stand beside a dying person and use this meditation method to split their own soul through that person's Death Force.
After finishing the book's third section, Avada closed it. He had no intention of reading any further for the time being.
The knowledge in the book was still difficult for him to understand, and studying it by force would take