KONOSUBA -God's blessing on this wonderful world! Episode 4: Explosion Magic for This Formidable Enemy!
Episode 4 of 10 of KONOSUBA -God's blessing on this wonderful world!, aired February 4, 2016, 25 minutes. Available with English subtitles and dub where released.
Episode summary
All of the weak monsters have gone into hiding since a leader of the devil king's 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 Megumin's training, which consists of unleashing explosion magic into an abandoned castle.