Shinigami no Kikan ~Assassin~

Once, there was a man feared as the strongest hitman in the underworld. His code name was “Nightshade.” Master of a thousand techniques that sever the human nervous system, he could strip his targets of all five senses and lead them to certain death—a “Reaper” known to everyone in the criminal world. But that man no longer existed. To protect a certain girl, he defied an order and was executed by the very organization he served. Seventeen years after his death, no one could have imagined it: the man has been reborn and now lives as an ordinary high school student.