Valentine Morgenstern (to Clary): I am doing this for you, and for your brother, and for the rest of humanity. Clarissa, this planet is under siege by demon-blooded creatures, intent on death and destruction. Once I wield that sword, the Downworld will no longer be part of our world. And the lives of my children… will be that much safer.

From Shadowhunters – Season 2 Episode 10: ‘By the Light of Dawn’ (2×10)