What are the major countries, what are they known for, how have they influenced the world, what their culture is like, and why are they important?
Vietnam and Thailand in particular.
Vietnam had been a Chinese- founded colony until the Empire broke apart in the 900s. The country continued to be a vassal of China up to the 1100s. From the 11th century onward, Vietnamese Kings began to claim kingship even though they still sent tribute to China as vassal.
Thailand was a underdevelopped tribe/ vassal of the Khmer Empire, modern day Cambodia, until the 15th century. After that, the Thais began to swallow the Khmer Empire.