Blood...she had been born and raised in it. War isn't glorious, it's just what they tell soldiers so that they'll risk their lives for the sake of the cause.
Death wasn't and hadn't ever been a new thing, it was older than the earth itself and had a circle of life and death throughout it's history. Growing up seeing it changes you.
If you grew up seeing it your whole life you would think nothing of it, killing off the fear by watching blood splatter morbidly across the walls and ground. Dripping from the ceiling and landing on whatever lies beneath.
Seeing it, changed her. Made her think that was the only thing that made sense, death made her undeniably morbid, a fascination with different ways to die made her kill.
Her first animal was when she was five, watching as it struggled underneath her booted foot as she watched from above with wide eyes as blood poured out of the creatures mouth. She had then crushed it's head to put it out of its misery.
Her first human was when she was fourteen. She had watched the light flee from the mans eyes, revelled in the power and then was disgusted with herself for liking it so easily. Death wasn't easy, for anyone.
She kept that, the image of that man in her mind, she remembered everything about his face, who he was, what he did for a living.
She remembered the blood.