The best way to illustrate the relationship of the comparison is a country using a comparative advantage can create a merchandise at a smaller opportunity cost, even though a different country has an absolute advantage in the manufacture of all those goods.
If I understood your question correctly, then the answer is "it depends". Sometimes, individuals have a large impact on starting a war (think World War I where one individual caused the war to start), other times groups of people have also important roles in starting a war (think World War II).