Why did the shura sword kill Qin?

Shura heaven and earth repaired Luo Dao to give Qin life because he valued Qin life more and hoped that Qin life would grow up. Not only to protect Qin's life, but also to draw out the opportunity behind it. We should also use the fresh flesh and blood of Qin life to nourish the cracks in the shura knife and suppress the wandering souls inside. It is also hoped that through the killing of Qin life, more ghosts will be swallowed up and enter the shura knife.