There are always wars going on. It happens physically and spiritually. War is apart of nature. Animals are in a constant war over food or terriory. People war over ideas, territory, principle, and the list can go on. Two groups disagree and fight. Most of the time neither is wrong or right, its just a matter of perspective, each believe theirs is the "right" side. Souls are eternal so unlike the physical where war ends in death or defeat, spiritual wars end when one side is obviously stronger, an honorable "win" occurs, or the goal of the war on one side is met. No one truly "dies" but they can be damaged from the battles.
I'm not sure which "war" you are referring to. But just as the elements oppose each other, nature spirits and "spirits of" this or that at times become entangled in disagreement or dispute. Greek mythology demonstrates the endless battles quite well. The celtics believe in the war between the Oak King and Holly King who battle every year.
Christians, Muslims, and Jewish beliefs feel there is a battle of good and evil going on at all times. But "good" and "evil" in the spiritual does not exist. It is a physical world, man made term for what is for and against the morals and values of the individual. There are however powers of creation/preservation and destruction that work together yet fight each other. Natures way of creating balance. It's the yin and yang of life's ebb and flow.