I don’t use fantasy species in my world on any larger scale ( by that I mean I don’t have anything like orcs or elves a species that is on equal terms with humans). As such in order to diversive things I have bunch of human ethnicities/nationalities. However I try to focus mostly on cultural differences then any racial ones.

Major cultural group include:

Western, Eastern, Heartlands, Scivians, Great Desert, Islandfolk that are further divided.

For example Heartlanders culture share common cultural heritage in form of Imperium of Chains. But after dissolution of Imperium different Heartlander cities/provinces established themselves as independents nations and with time they started to diverse.

Dealeonians stayed relatively the same ( by that I mean most diffrences between Imperium culture and Dealeon culture is a result of passing time)

Cirians were at one point successfully conquered and for a long time majority of Cirian land was under control of Avissians ( who belonged to Desert cultures) eventually lost territory was reconquered back. But long period under Avissian influences resulted in two Cirian cultures, Souther Cirians which mix elements from Heartland culture and elements from Avissian culture and are rather Cosmoplitan, and Northern Cirians which tried to maintain old traditions but the presence of “enemy” near the border also caused a push toward militarization and xenophobia.

Haansetic culture is a result of similar situation to that of Ciria, at some point after their declare themselves an independent country they were invaded and occupied by Scivians for around a decade. This caused change from monarchy to the form of democracy and greater focus on individual freedom . This freedom focus was permanently welded in to the nation identity after two sub sequential occupations ( one by Dealeonians and another one by Westerii) and uprisings.