Devil's Diary.

Cheon Nara, whose name literally means ‘heaven’, is a normal lady working a normal office job who suddenly starts seeing glimpses of a man in suits smirking at her. She lives alone and of course, freaks out when she feels that there is someone following her on her way home and makes the decision to buy a taser. It turns out that the man is no ordinary man; he is a devil who appears before her, black wings and all, to offer her three wishes. Nara’s response to his revelation is something Mr. Devil has not prepared for: she completely ignores him and his offer, doubting her vision. He tries to prove his identity, only to lead her into believing that she has a disease and has started having hallucinations.