YOu could also call an enemy a fiend or an opponent, hope this helps :)
Enemy
I think that it would be an enemy
An archfoe is another name for an archenemy - a particularly strong enemy.
Foe Rival Nemesis Villain Opponent
Another Public Enemy was created in 2005.
Enemy is the full form of the word enemy. It has many meanings, including someone who hates another (and vice versa) or someone who attacks another.
its when you give a another blow to the enemy or let the enemy hit you
enemy
One hostile to another; one who hates, and desires or attempts the injury of, another; a foe; an adversary; as, an enemy of or to a person; an enemy to truth, or to falsehood., Hostile; inimical.
Get Along With You Enemy Or Kill Your Enemy Or Make Him/Her Disappear
man is the enemy of another man
Gerald