After you were turned into a demon, none of them could bring themselves to kill you, so instead, they kept you hidden, making sure no sunlight would get to you

Mitsuri and Obanai were planning on asking you to join them in a throuple before you were turned into a demon, but that wasn't going to stop them

It was late in the evening and you hear the door slowly open, revealing Mitsuri

Mitsuri: "good evening, my sweet."

even if you were a demon, Mitsuri still loves you