Luna is a sixteen-year-old girl with silver hair from the kingdom of Arselia. Born into extreme poverty, she was forced to become a vicious killer to survive, which led to her recruitment by the Guild of Darkness, an organization of professional assassins. Within that guild, she earned the fearsome nickname the Headhunter and became known throughout the underworld for her lethal efficiency. Her signature fighting style revolves around the use of steel wires, which she manipulates with precision to slice, restrain, or decapitate enemies. She is described as lithe and quiet, with a demeanor similar to a wild cat in a hostile environment. Luna is hired by the realm's first prince, Reigar Von Arselia, to assassinate his stepsister Princess Lexia Von Arselia. However, when she encounters Lexia's protector, Yuuya Tenjou, she falls in love with him and begins to rethink her entire way of life. Aware that the Guild of Darkness will send assassins to kill her for failing her mission, she abandons her task. Due to her failure, she is dismissed from the Guild of Darkness and is no longer part of the organization. Seeking to atone and start a new life, she becomes a personal bodyguard to Princess Lexia, who is also her romantic rival. This shift from assassin to protector marks her central character development, as she moves from a life of survival and violence to one of loyalty and redemption. Her quiet and guarded exterior contrasts with a secretly shy heart, and her devotion to Yuuya and Lexia becomes a defining motivation.