If a War between North Korea + allies and South Korea + allies. Who would win?

If the criteria for winning is who will overrun the Korean peninsula, then North Korea and allies (if you truly think Russia and China will jump in today, which is unlikely). They have way more manpower they can expend on the mainland, and its far cheaper for them to send troops to the Korean peninsula. SK/USA/Jap will win in the long run though => USA's dominant naval power will absolutely destroy their economy as the war goes on.

This has already happened from 25 Jun 1950 to 27 Jul 1953. It was not classed as a 'war' as such but as a 'police action'. There were no winners and no losers it simply ended in an agreed ceasefire. There is plenty of information about this online. However should this start up again, as it may well do, and it was fought with conventional weapons I believe the same thing would happen. However, if the North Koreans have developed nuclear weapons they would not hesitate to use them if they felt they were being beaten. If they did only God knows what the outcome would be. Poseidon

NK is outgunned i only see a few allies that they could have but you never know and god i hope that a war with NK goes down that Includes US involvement. The last thing i want to do is get deployed into NK. Ill go to iran ill go to the heart of the terrorist but fear going to NK

The United States would win. Russia and China would remain neutral. No one is going to send their children to die to defend North Korea, no one except Kim Jong-un.

NK+ allies. Nukes, they don't mind.

It would be a tie again. If NK attacked they would be pushed back, but china and russia would have no part of US influence in north korea so the US and south koreans would respect that and not encroach the 38th parallel. It already happened once in 1950, and they learned the hard way to respect China.