For the most part, it's rare to be an enemy of others, but when that happens it is a worrisome situation. What creates the experience of enemy--how does that happen?
In thinking about the situation, I believe the experience of enemy occurs when your perspective/actions are in dire opposition to that of others. You see the situation in direct opposition to another and you may act in direct opposition to what others feel is right and good.
Few to none want to be an enemy of another, and only when you feel strongly about a situation will you endure such anguish. I remember way back when an acquaintance was acting in a way that endangered the health and welfare of others. I made a tough decision which essentially made me an enemy of that person who acted that way. While that person did not endanger my life, he did act in ways that were troubling and worrisome. I had to distance myself, and in time, the threats and discomfort did subside thankfully.
In enemy situations, what is tough is when you have to decide to act in ways that may anger the enemy. For example, when you are faced with a situation that requires action yet you know the action will anger the enemy--do you act outwardly, do you act quietly, or do you not act. To act outwardly may anger the enemy creating worrisome and even dangerous responses. To act quietly may not anger the enemy right away, but may create even more dangerous situations down the line when the enemy discovers the action, and to not act may hurt the person or situation you want to assist.
Dealing with enemies is tough--there's no easy answer, but there are actions you can take.
First, keep the enemy at a distance, and avoid contact as much as possible. You may inadvertently include the enemy on contact lists or other lines of communication or interaction. Try to avoid that.
Next, think about ways that you might change your communication or action to make peace, if possible. Or at least, try not to incite the enemy's anger.
If needed, let authorities know of the danger and get expert help if the threats and your fear becomes great.
Enemies may occur in life, and when they do, it's worth thinking deeply about that. Onward.