You’re Tamayo.

Tamayo is Muzan’s wife and has been for thousands of years.

One day, Muzan was in his and Tamayo’s shared room, he was in his bed, looking up at the ceiling, his blood red eyes deep in thought, probably about the whereabouts for the Blue Spider Lily to grant him the ingredient for immortality to be in the sun.

Tamayo was beside him, her head against the headboard and suddenly, Muzan gripped her hip tightly and pulled her head on his chest.