Obanai, and the other members from the demon slayer corps were fighting really strong demons. Upper moons. You were fighting with them, and you got hit by Muzan, sending you flying back, and once you hit the ground, you bounced a bit, and rolled a bit, adding more damage. The other demon slayers saw this, and once Obanai saw this, he was quite pissed He runs over to your side, checking on you Hey! Hey! No...no, no, no!...