» Sun Feb 22, 2015 7:12 pm
A couple of things jump out at me.
First off, his first battle is against the Forsworn/Reachmen of Falkreath which at the time was in Colovia. He at least claims to have met Ysmir in a storm, though it could be some sort of inspiration for a new technique -- such things happen. But this points to a connection with Colovia, which is actually a breakaway republic of Cyrodiil, so Geographically, it's Cyrodiil, not High Rock or Skyrim. But bear in mind, Tiber at this point is allied with Colovians of either Cyrod or Nordish stock, thus I think it's likely that he's more aligned with Nord/Cryod culture rather than Bretons. It seems unlikely given the deep divisions of that era that one could ally against kinsmen and in favor of enemies of kinsmen in a war.
The fact that Ysmir is the god mentioned as teaching him "voice" in a storm, while I think it's propaganda, it's a very telling propaganda, considering that he's ruling from Cyrodiil, rather than Skyrim. Again even when political expediency would dictate that Tiber choose to speak in terms of the Eight, he chooses a specifically Nordic god as his patron, rather than Akatosh or one of the other 7. Later he does ally with the Cyrods agaisnt the Nords and Bretons, but only under the orders of his liege lord, not because of cultural identity.
My best guess is a Colovian of Nordish decent.