To get technical its World War IV, not III. The Third World War ended with the fall of the Soviet Union. Although these World Wars take alot of lives, all World Wars are campaigns of the rich and powerful on the grand scale, with a basis of resistance built upon philosophical rightisms. WWI was formulated by the struggle to dominate Colonialism, with an undertone of blind nationalism based upon Elitism, militarism, and secret alliances. WWII was formulated by the struggle to assert revenge of German torts, with an undertone of blind nationalism based on Fascist versus the 'Free' world. WWIII was formulated by the struggle to maintain nuclear empires, with an undertone of class warfare based on Communism versus Capitalism. WWIV is formulated by the struggle to maintain crude oil dominance for the G8, with an undertone to blind Ismlamic fundementalism versus 'infidel' secularism.
The concepts that generate 'World War' are based upon English Elitism, and have nothing to do with Germans or Japanese people. The recurring theme of the times have been a potent force sets a parameter and makes an example of the impotent force, the impotent force being one that is non-submissive and dangerous to anyone other than the potent force, the parameter being such that the impotent force cannot by nature stay within which in turn means the impotent force willingly crosses the boundary, followed by the potent force always ends up putting the smack down on the impotent force. The fact that these wars cross so many borders is the only thing that sets them aside from the classic meaning of the word, "war".
The winner of any war basically gets to rewrite history with them as the 'good guys'. If you want to be practical, its safe to say the 'good guys' are good because they win. In WWI the 'good guys' struck first, with a Slav commoner killing a Hun arch Duke. (It just so happened that Slavs make up alot of Russia and Huns make up alot of Germany...) In WWII the 'good guys' struck first in Europe and Asia using economic sanctions, blockades, and hostile military force. (The English and French struck Germany with punitive settlement for WWI and then rewarded Hitler for his aggressive actions elsewhere with an appeasement, knowing full-well that Germany would eventually be forced to fight because of the original settlement. The Japanese, choked by America's blockade, struck Pearl Harbor then went for the land grab knowing full-well America's response.) In WWIII the Allies struck first. (The Allies setup an aggressive post-WW2 barrier against the Soviets, appeased the Soviets by watching them land grab what would become the Iron Curtain, then setup a Containment Policy that slowly put the noose around the Soviets. Luckily it was a non-nuclear end.) In WWIV the allies struck first, outright supporting dictator after dictator. (The Allies setup an aggressive containment policy against Islam by installing those puppet leaders, had an appeasement of the Muslims by granting them help in Afghanistan and Chechnya, then setup a Containment Policy by invading Afghanistan and Iraq.) Soon even WWIV will pass with the Islamic World crumbling. Of course these are wild simplifications of real global issues, but they aren't all that inaccurate..