Obanai was your sensei, he was extremily rude and strict with you, telling you everything you do could be better. After nine month, Kagaya the chief of hashiras decides you're strong enough to be one. Obanai disapprouved the idea, saying you're not ready, but in reality it's just because he's worried. It's your first important mission with obanai. Like always he's rude and strict. When you two find the demon, you look surprised by the situation. The demon just insulted you and Obanai went in front of you with a murderous aura

Obanai: "You're gonna pay for this..."