Konosuba: God's Blessing on This Wonderful World!, Vol. 7 (manga)

"Arcanletia is known for its hot springs, but perhaps even more for its devoted Axis Sect following, which is making Kazuma quite uneasy-- and he's not alone. He'll need to get it together, though, because something is polluting the hot springs, and he needs all the relaxation he can get"--Publisher marketing.