I once met a girl who believes that every human has a companion demon . that demon has his own personality and thoughts . " it's the reason we get our darkest thoughts " she said . " and I believe he can kill the person he's keeping accompany of . " .
 her story was long , frightening to the ones who were setting around her yet boring to me . It was nothing but pure superstitions , a scary tall to scare children in a summer camp or something similar  . though in the end she added , " you might not believe me but  ... i've seen it with my own eyes ... after all ...  that's how my younger brother was killed !   so ... be careful of those few minutes before you drift into your sweet sleep , it could bring your own death .. "