Kyon sighed convulsively. The rat obeyed him completely and didn't resist at all. The animal had turned into a shell that he could easily control. The knowledge and experience the rat had gained were nothing but echo of the mind it had left behind. Without the consent of the soul the animal didn't know what to do and wasn't sure if it was worth doing at all.
If Kyon was dealing with a human being in the place of the unfortunate rodent, it would be terrible. The person would turn into a being with no will power. They would obey every word of the one who had a soul and the same frequency of the body. Instinctively, they would consider the commander more important than themselves. Absolute obedience. Zombies lack a command center that gives freedom of action, confidence and purpose. Any subjugating formations can be removed, or they may contain bugs and work incorrectly. They can be resisted, albeit insignificantly. But in the case of zombies, they are nobody, real spineless puppets.