Some are just born bad, and that's all there is to it.

You might want to put some clothes on' suggested Jace 'I'm all for the bra and panties look, but you don't want the Silent Brothers to die of excitement

Listen to me. I am leaving, but I am living. I will not be gone from you entirely, Will. When you fight now, I will be still by you. When you walk in the world, I will be the light at your side, the ground steady under your feet, the force that drives the sword in your hand. We are bound, beyond the oath. The Marks did not change that. The oath did not change that. It merely gave words to something that existed already.

There was an electric anger in his gaze, and a sort of challenge that made Simon long to hit him with something heavy. Like a pickup truck.

He'd felt like a jack-o-lantern for the past few days, as if his guts had been yanked out with a fork and dumped in a heap while a grinning smile stayed plastered on his face.

I've always been told my presence brightened up any room. One might think that went doubly for dank underground cell." (Jace)

Mundane humans create distinctions between themselves, distinctions that seem ridiculous to any Shadowhunter. Their distinctions are based on race, religion, national identity, any of a dozen minor and irrelevant markers. ~ Valentine