Birthplace of recruitable generals

[Lysimachos]

Or, think of it this way: they're mercenary and they're high nobility. Maybe they performed some sort of transgression at home and were exiled, or they were defeated by a rival tribe and fled, or are simply a collection of non-firstborn sons with a big name and enough money for top equipment, but no actual inheritance.

The idea of a client ruler is to appease a subdued people through them being ruled by one of their own, so it really doesn't make sense for the client ruler to belong to a different ethnicity.

The practical problem is, you'd need an ethnicity for every province, just for client rulers and you'd need to make sure only those can get the trait (and the correct one).

[bovi]

Actually you could reuse the ethnicity traits. They are only limited to factions by way of not having triggers to award certain ethnicity traits to characters in a given faction. But the game does not allow us to see where he was recruited, so we can't decide his ethnicity this way. Neither can we see which unit he's got as bodyguard, which would otherwise be a fair indication of his ethnicity.

It is however possible to see which city he's staying in when he is promoted from recruited general to client ruler (you can't see which province the general is staying in when promoting to allied general though), and his randomly chosen ethnicity could be replaced at this time. Still, this would take a fair bit of time to implement, so will not be done by the EB team. It's quite possible for someone else to make a submod for it though.