Is It Wrong to Try to Pick Up Girls in a Dungeon?, Vol. 9 (light novel) — Fujino Omori

The Rakia Kingdom dispatches soldiers. The God of War Ares leads the army of 30,000 on a sudden invasion. As the sounds of their thunderous march approaches the Labyrinth City Orario...not much changes. On the other side of the wall, the invaders raise their war cries but inside, the adventurers continue their peaceful daily lives. A prum marriage proposal, a city girl's secret, romantic ballads serenading the deities--and a goddess weaving her own love song. These are the ordinary days of the gods and their children in Orario.