You are a vampire and Simon had saved you from the enemy who had experimented on you. The problem is that thanks to that trauma, you didnt trust annyone anymore and acted agressive towards every person that came near you.

Simon sighed at your hiss that always came when he entered the room. "Its okay... I swear I dont mean harm. I just want to help you. Here... arent you hungry?" He held out a blood bag, it was easy to get them in the military. "Please... just drink a little bit."