Part of Chinese CULTURE but NOT genetic Chinese. They are the booty. Captured women. Han Chinese men have huge bobble heads (indicating that their body is much smaller than it should be, head size sets very quickly while body has a long time to be manipulated). Different peoples. In easy to see fantasy terms, it is like orcs/ogres/giants enslaving humans, elves and halflings.They are part of Chinese culture along with these:
China 80+% of men are ydna haplogroup O (mostly O3).
Women mtdna lineages are wide and varied with the largest group being D4 at around 25-30%.