For example...
By choosing Priestess as the origin, the player would receive the "Venomous Blood" passive ability, which changes a lot in the gameplay, and also limits magic to a single unique school.
Playing as a character from Volder, the character ignores most of the magic, but also cannot learn it himself. Plus, instead of a very important faith, he develops atheism.
A character from Ammantur crafts things that will make others envious, but there is no magic, and without crafting, he will have a very hard time due to lowered characteristics.
A pure-blooded cultist specializes in a ritual branch that is inaccessible to others.
And so on.
In general, there are only local humans among the races, but each origin differs in gameplay, and not just in numbers.