Protect Her

Although it has long been established that one becomes a Grim Reaper if they commit a great sin in their past life, here Grim Reaper learns that he was King Wang Yeo, the boy king that was once protected by Kim Shin, When Kim Shin confronts him, he tells him that on the day he had Kim Shin killed for supposedly being a traitor, he killed all his soldiers as well as his family, including his Queen, who was Kim Shin's sister. Over the course of the series, he shared with Reaper about his life and the story of the young king in bits and pieces. Yet he still wonders what he did that was so wrong that he had to suffer the fate of being a reaper and forgetting his memories.