China was unified by the Qing Dynasty. Are Manchu people from Northeast China? I don't quite understand how a place as big as the Central Plains was unified at that time.

Today's Northeasters refer to the descendants of Han people who immigrated to Shandong and Hebei in the middle and late Qing Dynasty, most of whom are descendants of Shandong people, accounting for 80%.

Manchu, short for Manchu, is a nation different from Han nationality. Manchu, formerly known as Nuzhen, is a hybrid descendant of Mohong and Goguryeo. The Moho nationality originated from the Tunguska Valley in Siberia, North Asia.

Modern linguistics believes that Manchu belongs to the Manchu branch of Tungusic language family of Altai language family.

At the end of the Ming Dynasty, there were less than 300,000 Manchu troops and120,000 troops (50,000 Han people attached to the army), but they were able to sweep China, wipe out the strength of Nan Ming, Zhang and unify China. This is indeed a miracle.