KONOSUBA -Gods blessing on this wonderful world! Temporada 1 Episódio 4

All of the weak monsters have gone into hiding since a leader of the devil kings army has settled in near town. Kazuma, who had been focusing on improving his skills, is stuck at a standstill. With nothing else to do, Kazuma tags along with Megumins training, which consists of unleashing explosion magic into an abandoned castle.