Colonialism can create division even between people who have the same ethnicity, let alone different. One example of this is the relationship between the Tigrians of Eritrea and the Tigrians of Tigray. Both people share the same language, culture, and religion, yet they hate each other immensely. Eritreans esp consider Tigrians as inferior and don't want to associate with them, even though they belong to the same ethnic group. Nothing angers Eritrean Tigrians more than to be told they are ethnically identical to Tigrians in Tigry. All this hatred is the result of the indoctrination they got from the colonists who came from far away and told them they were superior. The colonists did this in order to create division between families and draw borders to facilitate their occupation.