Dakara Boku wa, H ga Dekinai.

From Yen Press: One fateful day, Ryousuke Kaga, a typical hopeless romantic and hopelessly perverted high school student, has a chance encounter in the rain with a beautiful girl. After graciously offering both his home for her to dry off in and his help for anything she might need, the mysterious red-eyed beauty thanks him by stabbing Ryousuke in the chest! To further complicate matters, the girl, Lisara Restole, is actually a shinigami–that is, a god of death–and Ryousuke has somehow unwittingly agreed to let her use his “essence” to remain in this world. But instead of shaving years off his life like one might expect of a typical shinigami, Lisara seems more interested in…leeching the letch right out of him?!