HAUNTRESS

Hiroshi Mori is an ordinary college student leading an unremarkable life, until one day he hears someone ringing his neighbor's doorbell over and over again. He goes out onto the landing and finds a strange woman in a trenchcoat―whose tenacious attention soon transfers to him. Stalked and harrassed by this monstrous woman, Hiroshi tries to find out the truth about her before she ruins his life completely. (Source: Kodansha USA) — Description from AniList community (anilist.co).