Fortuna's Eye.

Shinichiro Kiyama is completely alone in the world. One day, he realizes he possesses "Fortuna's Eye", an ability through which people whose death is drawing near appear transparent to him. It is a gift that torments him. Then he meets a cheerful, optimistic girl Aoi Kiryu who makes him feel at ease. Shinichiro develops feelings for her, but after a brief period of happiness, Aoi's body suddenly starts turning transparent.