Obviously, based on Su Ping's deductions, the purpose was sacrifice, devouring, or something of that nature. But if that was the case, what about the final step? What happened after these souls transformed into Black Swords? As it turned out, the Black Swords simply vanished the moment the next sword chime echoed. So, why did they disappear?
At this thought, a sharp glint flashed in Su Ping's eyes. That was it! That had to be the underlying Rule! It was far too difficult to locate the Heavenly Tomb's main body or whatever was hiding behind the scenes in this gray fog world. Since that was the case, why not use this Rule to actively welcome the entity's summons?
