U.s.
China helped the North Koreans and NATO helped the South Koreans.
America
Mainly the USA as when they occupied the South of the peninsula, the Soviet's invasion was halted and the Soviet Union and USA made an agreement to temporarily split the country a the 38th parallel. Thus, North and South Korea was born.
North Korea. The North Koreans attacked first and the Americans helped the South Koreans. Once the North Korean Army was surrounded, the Capitalists invaded NK. China thought the Americans were imperialists like Japan in WW2, and so helped the North Koreans.
China
China and Russia
China and Russia are two countries that supported the North Koreans.
China x
when the North Koreans invaded the South Korea. Most of the South Koreans were killed, tortured, jailed. But help of many other countries like US, Philippines, Japan, United Kingdom,and other African countries, South Koreans were saved. General Douglas MacArthur planned "Incheon landing plan" or known as 인천상륙작전 made the Koreans to ger their territories.
China
North Koreans don't believe in fun, after all, they are communists.
North Koreans are living under a very harsh communist dictatorship