Nemurenu Hitsuji to Kodoku na Ookami -A Tale of Love, and Cutthroat-

Kabukicho, Shinjuku. There's a love hotel here where I work as a live-in cleaner—or at least, that's my day job. By night, I suffer from chronic insomnia with just one cure: killing people. So I moonlight as a yakuza bigwig's pet killer, waiting for him to toss me a bone and order a hit so I can sleep. Might sound like a fine line to walk, but my life's pretty quiet. Pretty stable. Until I meet this call girl, Azami. Having sex with her got me a night of sleep so peaceful, I've been mulling over the idea of keeping her around. Thing is, my boss wants her dead, and if I bite the hand that feeds me, there’s my quiet, stable life out the door...