Is Zhu Meng from China or South Korea?

Zhu Meng is the ancestor of Koguryo, a minority nationality that originated in the mountainous area of Liaodong. The ancestors of Koreans are Mahan, Han Ge and Chen Han. They originally lived in the south of the Korean Peninsula, hence the name "Korea". So whether Zhu Meng is from China or not, at least he is not Korean.