City of Bones
How we cite our quotes:
The neck of [Valentine's] shirt gaped open a little, showing his scarred collarbones. Scarred, like his son's, like all Nephilim. A life of scars and killing, Hodge had said. (23.18)
If the Shadowhunters had recruitment posters, "A life of scars and killing" probably wouldn't be their tagline of choice. It's nowhere near as catchy as "Be All You Can Be."