Demons grave.

A young little girl full of life and stories finds the only red spider lilly and eats it, she goes mute and has the strength of a demon in a human body, has the eyes and sent of a human has fangs like a demons. muzan finds this girl and sees her rare beauty and strength, once he sees her fangs he thinks she possess the ingredients nessasary to make his medication to have him be able to walk in the sun.