Yaoi

Ein was a hitman on hire. A killer, a shadow, a death with insomnia, if you may.
    He had witnessed countless pairs of eyes dim as the light of life faded, leaving nothing but vile hollowness. Needless to say, the sight of a soul popping out of the dead body was a first.
    And it wasn't just any soul. It was the dead heir of Byers Holdings, the same guy he killed with his own hands. Turns out the rich boy Adriel had a horribly irritating and loud soul, but worst of it all - impossible to get rid of.
    Who would have thought that killing on a blue moon night could lead to being haunted?