How many deaths for a kill?

The ground of the arena mirrored the bleeding sky. They laid there stained in brutality, twenty hearts pulsated disdainfully, letting out their lifeblood. She rose among the corpses, magic burning into her retinas until they felt so hot that they felt cold. She was the imagined personification of death. Not a god, but someone they would learn to fear. Her ashen eyes fell on the boy conjuring the two floating metal blades that were shearing like chattering teeth. As she walked closer, her eyes paused on the weapon. She could tell that it was tailormade for him. A masterpiece that the baron would have her filch. Briefly closing her eyes, a silent complex of mental gears seemed to move jauntily with excessive thought. The boy was bewildered by the soft and nervous expressions of the murderess. He didn't dare speak, dragging his heavy body against the sand as he dug himself out with his slender yet bulky weapon. A minute passed. Then two more. It was like she fell asleep, hardly breathing.

"How old are you?" she suddenly blurted out, breaking the suffocating silence. As soon as he heard her voice it felt like he'd been stabbed in the heart by its melodic beauty and power.

"I'm told my master said I should... I will leave one alive today."