The Shadow of The Moon

Portus, a nation part of the Lorien world, led by Khaos, the strongest knight and Queen, has been haunted by a lurking executioner whose victims are death sentence ranked criminals. Khaos along with Han and Dracarus, her helpers, go on a long investigation to find the one's identity.
Dracarus and Han later on befriends a group of sculpture students where a secret lies by one of them, followed by forbidden feelings and emotions.
Not only is the executioner's case solved, but also many other incidents that had been in the shadows of Portus for centuries.
Every single one of them, connected to the same person, who steals the protagonist's place as the investigation develops throughout the story.