Well, his name is Tiber Septim, the Nords call him Talos, the Bretons don't consider him a god but instead a hero and call him Hjalti Early Beard(well, in high rock anyways). AAlso, the Imps are the ones who call him Tiber Septim.
And he isn't just a deity(he might not be a deity at all). he is founder of the third empire. in ESO's timeline spot, we are in the interregnum of the second empire, specifically the year 2E 582(second-era 582). in another 200 Tiber Septim conquers all of Tamriel, forming the third empire, and upon his death is declared a god.
EDIT: actually in about another 300 years nvm the 200.