Could it be that Bassianus is the decendant of Gemellus Axius(Oblivion) or/and Maximian Axius(Skyrim/Dragoborn).Both Gemellus and Maximian are Imperials but Bassianus is labeld a Nord.
Gemellus is a commoner in the Imperial city and a servant to Jakben, Earl of Imbel.
Maximian is a legion soldier stationed at Fort Frostmoth and his skeleton can be found there along with a knapsack and letters intended to his wife,A woman named Selina,in the letters it is metioned that they have children together that go by the names of Siricus and Atia,so what i wonder is,could it be that either Siricus or Atia are the parents of Bassianus and that Maximian and Selina might be his grandparents and might it be possible that Selina lived in Ivarstead or that either or both her children moved there only later to see birth to Bassianus who the then despite having Imperial heritage would still be counted as a Nord and at the same time explain his Imperial sounding name,could it also be that Selina was a Nord herself?