Korea - UN or...?

[Legbreaker]

The books only include US and Soviet units as being in Korea and no mention of the North or South Korean forces.
Additionally, a quick study of the unit histories of those involved seems to indicate the conflict followed a similar pattern as occurred in 1950-1953. The US only had one Division in the region at the beginning of hostilities with several more arriving over the next six months (give or take) and the Soviets took the place of the Chinese 45 years before, coming into the picture in late 1997.

Given what is therefore likely to be North Korean aggression kicking things off (again), the technical continuation of the 1950's war which involved the UN on the side of the South, and the involvement of Australian and New Zealand troops (neither of which are members of NATO), as well as the originally intended involvement of Canada, I'm interested in hearing peoples opinion on who's backing the South this time.

Is it the UN (I tend to think so) or has the US gone to bat for the South off their own backs and called upon their allies to assist?

Why?