this is what I'm starting to think: Zurin Arctus is Wulfharth (the Underking before Daggerfall) in Daggerfall, but Arctus is the "dominant" personality in the game, which is why he talks as such. When Zurin (Underking) gets the Mantella, I think he does more than just become mortal and die: I think he acheived apotheosis. But something was confusing me though: Tiber wasn't killed in the confrontation, though, so how did Tiber Septim become Talos? If the Enantiomorph works the way I think it does, Zurin Arctus is Tiber Septim because Wulfharth the Underking was the "Trinimac" in that Enantiomorph.
Along with the Underking, who represents a number of heroes and has a number of names, such as Ysmir, Tiber Septim, who also has a number of names, such as Hjalti Early-Beard and Ysmir again, these elements comprise the entity of Talos, the god of War and Governance.
...Right?