The entire middle east doesn't have the resources, fighting power, moral, organization... or anything to fight any "world wars". Sure, they have their capital cities but in the end the majority of their population is tribes whom have been at war with each other since the beginning of civilization. There would have to be a revolution of historic proportions to get the middle east organized to any reasonable threat. They have "terrorists", but a minority group of guerrilla fighters an army does not make.
Its like expecting Africa to just suddenly rise up as one and fight the world. With what? They have oil and resources, but what to they produce? Most of the middle east and Africa survive off of weapons we sold them in the cold war, and what they managed to steal after said war. Iran's terrifying air force? Old f-15s that went out of style when we invented planes that can destroy their entire "airforce" over the curvature of the earth. If it came down to it, most first world countries could destroy most of the middle east without ever stepping foot on the country itself.
Whatever war is coming next the middle east may cause a spark but its hardly a "world war" threat. The Middle East is definitely on the edge of a bunch of civil and country to country wars thanks to our meddling in that area over the past 70 years, but I'm pretty sure they are more preoccupied with who is a jew and who isn't than trying to fight the whole world.
As far as N. Korea goes... in my opinion, laughable at best. They don't have the population for it, nor the resources, moral, or, well, the money. N. Korea, despite its best efforts to show otherwise, is poor as dirt with a substandard "military". Their "military" is like a bodybuilder's body; its nice and thick, but in the end he can't move much, would be a pretty poor fighter, and also has a small d***. They can flex all they want, but a kick to the head and they'll fall like a tree.
Especially with China having a greater chance of allying with the United States, and Japan being more than willing to destory Korea... the only danger N. Korea poses is a possible invasion of S. Korea, which would end up being exactly how it was in the cold war; a proxy war that, while bloody, is still confined to two relatively small countries.
Problem with the WW3 scenario right now is that most first world countries are pretty damn comfortable with each other, and most third world countries are more preoccupied with killing their neighbors than fighting the first world countries. Chances are another World War would be sparked by a previously first world country, or a first world country that got powerful enough.
If you really, really pressed me I'd squeeze out a future China superpower when they get through their current industrial revolution being heavily involved in some way, but going by history I'd rule out any theories on direct war with the United States. We share the advantage that Britain has; we're essentially giant islands. You'd need a near invincible navy to get across the ocean to us, as well as an insane amount of ships to carry enough troops and equipment. Not gonna happen.
Chances are it'll be a land war in Asia like it has been forever. Europe will fight itself, the Middle east will fight itself, and east Asia will fight itself with overlap while America sits back and watches unless Canada tries to go to war with us.
But, you want my opinion on sides? Simple: The Internet. Those connected with each other will ally, and countries that heavily censor and nearly shut down from the rest of the world will do the opposite. Propaganda is harder when you can easily talk to the rest of the world, and I'd put money on countries that block out of country internet being on their own side from the web.