A soldier?
A person who believes that war is wrong is called a "pacifist".
You would call them veteran!
pacifist
this person is called a soldier
A warmonger!
A turncoat.
This is a Confederate.
Admiral
anchor It is true that many people call this person the "anchor", yet it is also true that many call that person the "caboose".
Someone who does not believe in participating in war is known as a Pacifist. They believe that war and violence are unjustifiable and that disputes between nations can and should be settled peacefully.
you call this person a "confidante"
You call the person a victim.