The Greatest Demon Lord Is Reborn as a Typical Nobody, Vol. 5 (light novel‪)‬

THE PAST ALWAYS COMES BACK TO HAUNT YOU
The end of one adventure marks the beginning of a new one. Ard and Ireena are summoned to serve as the queen’s guards in the holy city of Megatholium. Just when Ard thinks he’s managed to shake off one Heavenly King by leaving the city, another seems to take its place. This time, it’s Lizer, the old general. Apparently, he’s claiming he’s the pope of a religion that worships the Demon Lord…and he intends to brainwash the people to achieve world peace. Ard and Ireena begin to expose his nefarious plan, but it seems the pope has plenty in store
to keep them on their toes!