u/Amazing-Point3540

english isn’t my first language, so please excuse any mistakes

I’m looking for a one-shot smut manga that I believe is yandere. The ML is a demon/monster/ghost whose face is constantly covered in a strange black goo. the protagonist has short black hair
He showed up at her house out of nowhere, and you all can imagine the rest. The only distinctive thing I remember is that gooey substance on his face and he was soo toxic