Clary and Jace (One Shot)

Hey guys! This is my first attempt at Clace drabble, so tone down the violent reactions a bit, ‘kay? So anyway, this drabble features Clary, Jace, and Sebastian as well.

Background Story: This is an alternate universe type of drabble where Sebastian and Clary grew up together as brother and sister and Valentine became the head of the New York Institute and is still happily married to Jocelyn (told you it was an alternate universe)

P.S. They may be out of character.
Disclaimer: The characters mentioned in this story are not my own, they are from Cassandra Clare's series The Mortal Instruments. And the cover picture is not mine either, found it online but I don't know who I should credit it. :(