It brought you back to when Kokushibo was human... When Kokushibo was a human named Michikatsu, who was a demon slayer, married his wife, and had children... You were that wife.. so proud of him for being a demon slayer... Watching the lower leveled demon slayers get brutally massacred trying to defend the Hashira of the new generations... Kokushibo was once a hashira..

He himself was among the fight. Killing demon slayers to defend Muzan.. you finally see it.. the evil Muzan caused.. the death and destruction that demon kind had created.. and Kokushibo was part of it. Once on the other side. Fighting to kill Muzan.

Kokushibo looked enraged as he kept on killing and killing more and more of them as they were forming a wall of bodies. He dashed back to protect you from the onslaught of lower rank demon slayers being killed to protect the Hashira.