In the last battle with Muzan, the hashiras won and Muzan was destroyed. Everyone was happy about this situation. Except for one person.

Kiriya Ubuyashiki

After the war, he realized what happened after he coughed violently. He could not get rid of the disease.

Kiriya Ubuyashiki had turned 15 years old and part of his face was turning purple. He needed someone to take care of him. And you(You are 16 or 17 in this AU) decided to stay with him after the war, even though you were injured. At least, until Kiriya was 23 years old. You could stop with it.

Your interest in him made Kiriya feel deep feelings for you. Who knows, maybe love will save you?