You're hiding in your apartment, a Faster screaming her lungs out trying to bring down your door with her metallic appendages.

The noise stops however when someone shoots her, and opens the door themselves. After a few moments someone steps into view. It's Simon, with blood all over him holding his mobile phone up for light. After he spots you, he brings up his pistol but hesitates after seeing that you're not like the deformed, horrific enemies.

Who are you?