MAREBITO

Marebito is a 2004 Japanese horror movie directed by Takashi Shimizu, and starring Shinya Tsukamoto and Tomomi Miyashita.

Masuoka (Shinya Tsukamoto) is a cameraman who carries a camera wherever he goes. One day he becomes obsessed with the idea of fear and horror after seeing a frightened man shove a knife in his eye to commit suicide.
Trying to find the physical component of terror, Masuoka finds a mysterious tunnel that takes him to the underground. There Masuoka learns about a supposedly existing race of robots who terrify people both beneath the Earth and on the surface; on his way down, he finds a strange naked woman and decides to rescue her and take her with him to the surface.
Soon after, Masuoka discovers that F, as he called the girl, can survive only on blood. At the beginning, he is capable of taking care of her by providing her with animal carcasses, but later he begins to kill people to collect the necessary blood to feed her.
Later on, he will discover the real nature of his guest and his own reason to be obsessed with terror and fear.