Your inner-monster

Japanese monsters are totally different from Occidental one.
There also are much more frightening because they are not any entity that you can pinpoint and kill, something different from you. No no nooo. The Japanese monsters emanates from your dark side!

Go back to the 10th century: litterature is populated with spirits called "shiryu" 'spirit of the dead" - a specific dead person, and "ikiryu", spirit of a living person. These spirits can be both good and bad, while, usually, it is more "fun" if they are ill-tempered. In the famous Tale of the Genji (you need to read a few chapters of that), meet the beautiful courtisane, one of the many girls with who the Prince Genji falls in love, but this one, a bit more than the others. Well ,she dies at the end of the chapter, leaving the Prince in a state of deep sorrow and distress. She dies by the "hand" of the living spirit of another courtisane, who is deeply in love with the prince and cannot suffer to share him with others. Welcome to the imperial court of the 10th century.

Then, you also find less sophisticated creatures, like in the Door of Rassho. You might have read Rasshomon, a short story of Akutagawa. Actually, Rasshomon's spirit appears in the Konjaku monogatari, 10th century (not sure about the century though). Very bad. Do not read this before going to sleep. You might not wake up.

Have you ever met "oni". Well, a story for some other time. Oni are also sophisticated creatures, leaving outside society. They could even be humans. Very often malevolent but not always.

Then, you have modern monsters, like in "Ring".

The thing is, you cannot get rid of the Japanese monsters. They are you. They are your dark side. This is the reason for them to be soooo frightening. Do not watch or read before you go to sleep!