Five Reincarnations?
"Sha has a total of five cores which contains all of his power and are exactly like his five hearts. As long as they can be either damaged or destroyed even, that would deal a massive blow to him. But Sha is extremely cunning. He placed his cores in completely different worlds where we cannot go ourselves and these worlds are middle plain existence and will not let any outsiders into it. As for how sha went in is because he corrupted a being from those 5 worlds and let them become the carrier of his hearts or cores."
After Life Elder said to these, she stopped and Thunder Emperor continued in a cold voice,
"What you need to do is to reincarnate into these 5 worlds as a being of these worlds and damage the cores of Sha. These five reincarnations will also be your ultimate trial in becoming Rules and death respectively. As you complete the five reincarnations, you will truly become rule, and Su Yubing will also regain her memories and completely become death."