Fear.

Fear is defined as - a distressing emotion aroused by impending danger, evil, pain, etc., whether the threat is real or imagined; the feeling or condition of being afraid. This quote speaks the truth about fear, "Our deepest fear is not that we are inadequate. Our deepest fear is that we are powerful beyond measure. It is our light, not our darkness, that most frightens us." Fear is as much an emotion as it is a weapon, fear can also protect us and well as hurt us, but in my opinion fear is best use as a weapon to harmed those which we deem evil. Fear is necessary to attack evil, and keep the weak in line. My greatest fear is not being inadequate, and it is not my light nor my darkness, and it is neither being alone but it is having companion whom i cared for and losing them, losing those whom you have come to love for being there is worse than being alone. And just like Violet said in Ultraviolet "These moments, as beautiful as they are, there evil when their gone." that is the same type of pain felt when someone you care about is lost, for all that is left are the memories. Having only memories is my greatest fear.