Who were the enemies in Korea and Cold war?

TLDR; Cold War Era 1945 - 1991

• US/NATO vs. USSR/China/Warsaw Pact Alliance
• Democracy vs. Communism

Korean War 1950 - 1953; technically 1950 - Current

• ROK/US/UK/UN vs. DPRK/China/USSR
• Democracy vs. Communism

An Armistice isn't a treaty, North Korea still strives for reunification under communist rule.

Wow, I could give you an in-depth reply on this stuff but its probably better and less time consuming if you just read the Cold War, Red Scare (/Communism), and Korean War wikis.

But none the less, the "enemies" that you're referring to during the Cold War Era leading up-to the Korean War happens to only be the fear of Communism.

So, the Cold war started right after WW2 when the wartime treaty between the Allied forces came to an end. At this time; the US, UK, and USSR were arguing on how the borders of Europe's countries should be drawn.

(Skipped a lot of stuff like why USSR wasn't regarded as a superpower til 1949, go read up on it)

This promptly lead to a power-struggle between 2 forces, 3 if you count the NAM even if they did nothing, the US/NATO forces and the USSR/Warsaw Pact. NATO forces wanted to rebuild and establish a democratic governments while the WSP alliance wanted to invade and dominate the surrounding areas due to past conflicts. This later resulted in the threat of mutual assured destruction between the US and Soviet Russia and also the start of the Red Scare or the threat of communism spreading west.

Stuff like the Korean War, Vietnam War, Cuban Missile Crisis and Proxy wars, are just tug-of-wars with the US backing one side to help rid the area of communism and the USSR/China backing another to spread it.