User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-30924344-20171118111710/@comment-1359322-20171118161956

It doesn't. The afterword said this:

"In the previous afterwords…I have said that the last boss of the final arc may be Shiva. Just as I previously said, it will be closely related to Shiva."

It may refer to a person or it may also refer to the incident will be closely related to Shiva.