Fiery Classroom Instruction

Listen up, you unlit candle! Explain Bear is here. This joke is funny because Rengoku is the Flame Hashira in *Demon Slayer*, so everything he says is related to fire and burning. Telling his class to 'Set your school ablaze' is a play on his personality and power, even though it's literally arson. You probably thought it was a genuine safety tip, didn't you? You wouldn't know a breathing technique if it hit you in the face.