So I don't get it, what's your problem with having Imperials as a race separate from other humans?
Just leave it. One of the beautious things about how TES has changed is that they were radical in ways. some liked the changes, others didn't.
And you're taking as fact for this a several thousand year old song that is likely steeped not only in metaphor and exaggeration, but legend as well. Okay.
Pwned. I always like that perspective. yes this is a game, and as such not real, but the realness is always a fun bit to throw in. if this is a functioning world, even not our own and fundamentally different, the nature of people is to inflate and exxagerate. So while several things may be true 9the fact that Pelinal was something special, by birth or mantling, is not in dispute) some details may be different simply y the act of them being told by a person, or translated, or whateverelse.
Pelinal is said to be an avatar of the chaotic and unstable fusion of Akatosh and Lorkhan. I dont think that he traveled backwards through time, it was more like he was prophesying/embodying the future via his Akatosh half.
That is... very very clever. If he is embodied fusion of space-time, then I think he is both what you said, but also from the actual future as well. Instability in gad-men makes for fun conversations, just look at the tribunal.