They was a man who name was Grim Reaper, he has long nails and he is evil he is just like the devil he takes people soul. The grim reaper and humans do not work together but before he became the grim reaper he severed as a servants for a king he wanted the king to give him part of his treasures but he refused which made him to become hateful and thought only of evil, the king through him out because of this and he became more evil and made a deal with the devil and became what we know as the grim reaper. Grim reaper still wanted the king dead so he used his abilities of turning into a human to turn into on of the body guard after his mission was complete he did other missions to kill people so he change faces and names and after 20 years on one particular missions he was unable to complete it, he couldn't kill the baby boy and decided to train him instead he taught him how to use magic and how to kill people. He named him James he was very humble to the grim reaper and feel in love with a girl but he couldn't marry her because before the wedding he betrayed her that why the grim reaper told him never trust anyone except for me. 

A big thanks to jannie_rocks for the cover