User blog comment:B214/General Discussion/@comment-27083298-20160605005336/@comment-1359322-20160605014604

I don't know if he's popular or not but in Volume 13 he mentioned this:

"I don’t know after how many years it will be, but after “DxD” ends, I am having an imagination of wanting to write a story about him(Millicas) who is all grown up as the main character attending the school in the Underworld."

Well since Ishibumi already setup the Auros Academy, so i think the chances of this happening is quite high.