Answer:
Hey There. ☆~_____`▪\|▪`_____-☆~ I think the answer is: Civil war. Because For A example, let's take a look at the American civil war. The civil war was initiated by the union army against the confederate army. They both belong in different factions. The union army belong in the faction that wanted to be aoblish slavery while the confederates belong in the faction that wanted to keep slavery.
Hope It Helps!~ ♡
ItsNobody~ ☆