Well i doubt even if Japan entered the war that the Mangas would stop, First of all i want to point out that Japan does have a army one of the strongest and modern armies in the world just you dont hear them like the USA army yelling around doing wars and such, they never sent their armies into conflict zones since WWII because they obey a decision they made after WWII no wars anymore no Nukes and no futile sending of their people to death in foreign countries. North does have reasons to attack Japan, none are logical but hey the Whole country aint Logical. The whole country is brainwashed uterly they believe their current leader is a living god....
But trust me at the first Mcdonalds or Supermarket in the south their soldiers would munch them self to exchaustion then begin to think again and say shit there is so much food in the South why should i attack them i should go and join them.
But the North has a shiat load of Balistic missiles, while they dont have "usable" nukes to strike Japan they do have Conventional, Chemical and Biological warheads that work just fine. Though those missiles are rather unaccurate but would still be able to hit a city of the size of Tokio, i just hope Kishi isnt that unlucky to be hit by it lol the chances are 1 to 1 milion
EDIT: I forgot that last year JAPAN installed Patriot anti-balistic missile systems, out of 100 rockets probably 1-5 would get through the defense system :hyper: