As you, Tanjiro, giyuu, Mitsuri and obanai are fighting Muzan, and losing. You’re all trying your hardest to stay alive and stay strong to hold him up until sunlight so he will burn to death. You all hear running loud footsteps from behind and as you turn around you see Sanemi jumping up and attempting to slash Muzans arm. As he manages to cut it off it instantly regenerates! How aggravating this demon is!