If Tiber Septim did actually become a deity, wouldn't he be considered a daedra, considering he had nothing to do with the creation of Nirn, which is what defines the aedra from a daedra. Also, if he is an aedra and not a daedra, wouldnt he be invincible like the daedra? Because he never would,ve had to give up some of his own power in the creation of nirn.

Talos is neither Aedra or Daedra, he is just a spirit.

-What makes the Daedra a Daedra is that they chose not to take part in the creation of Mundus, Talos didn't chose not to help create Mundus, he simply wasn't around for it.

-And he isn't an Aedra because he didn't take part in the creation of Mundus.

So he is neither, he just IS.

Neither, that's part of why he's important.

Although technically yes, the Aedra are defined as ancestors and the Daedra are not, that really doesn't encompass the gamut of entities in each category.

For example, Malacath, Meridia, and (possibly?) Dagon must have participated in creation, having been respectively Aedra or Magne Ge. Yet they are now considered Daedra. Arkay (and sometimes Auriel) is by some accounts an ascended mortal and thus not a participant in creation, yet is ranked among them just the same. Some entities formed after creation and yet are still considered Daedra (Hermaeus Mora, Sheogorath), while other deities that ascended after creation are not counted among either party (God of Worms, ALMSIVI)

I think the categories are somewhat fluid, factoring in some bits of the ideology/alignment of the spirit in question as well the as cultural bias of the people groups who so named them. I'm sure men and mer argue over what qualifies.

As for Talos, he has taken over the mythic role of Lorkhan. If he's filling out the shoes of the very one who conceived of Mundus in the first place, surely it is not too odd to count him among the ranks of the givers?

The primary requirement for being either Aedroth or Daedroth is that the being in question is an et'Ada, a being of the previous subgradient. Talos is a risen mortal, a being of this subgradient--he has the power of an Aedroth or Daedroth, but does not fall into either category. Moreover, he took Lorkhan's place in the mythic, and I don't think Lorkhan has been categorized either.