This is Las Boss, Demon King, "Church" in front of Castle.

The impenetrable Castle of the Demon King - a small church built on the front. That was the last save point to serve as a base for the Demon King crusade. It is the youngest high priest's youth, Seychlid, who has been assigned to the fierce and harsh duty station of the demons. Now the curtain of "Neighborhood dating" by the Demon King Army and “The Most Powerful Saint” is up!? One or two volumes of the original are on sale! Comics volumes one or two are also on sale ♪ C.W ( https://comic-walker.com/contents/detail/KDCW_AM19200685010000_68/) Nico Still Pictures (http://seiga.nicovideo.jp/comic/38521?track=official_trial_l2)