Darker Than Black: Shikkoku no Hana

From BH007: One day, in the middle of (Tokyo), the Hell's Gate appeared. In the area coverd by the gate, the laws of physics do not apply. Furthermore, people living nearby have begun to develop supernatural powers, and are known as contractors. Among these contractors, is BK201, a contractor with power over lightning who is renown as one of the strongest reapers and for some reason, hated and hunted by most major world organizations...