Dungeon Builder: The Demon King's Labyrinth is a Modern City! (Manga) Vol. 11

Procel knows he's walking into a trap, but he's dead set on kicking down the doors of the Kriss Kingdom, the final stronghold of the Rigdolg Church. He's eager for a chance to finally settle the long-standing feud between himself and Balam, the Demon Lord of Darkness. Balam begins his attack, but when the dust from his destruction magic clears, Procel hears news that the Demon Lord of Darkness has died! Could it be true, or is it all part of Balam's plans?