Kinda like Russians always rule over Ukrainians and Poles?
Well, they don’t actually.
Poles conquered Muscowy in 1610, the only nation to have done so. And Russia or to be precise Muscowy at most ruled over half of the former Polish Lithuanian lands from 1831 to 1914.
Caste is different, you had the Hephthalites being added into Hindu society as Rajputs, etc.