Board Thread:Lore Discussion/@comment-39786381-20200120122306/@comment-34236415-20200120143934

I'm not an expert on this, but AFAIK aedra appears on Nirn through "proxis" (avatars or aspects). The Elder Scrolls series neither begin, nor end with Skyrim and aedra has appeared in both Oblivion and Morrowind:
 * Wulf appears to the Nerevarine in Morrowind. It is later revealed that "Wulf" is an aspect of Talos;
 * Ama Nin also appears to the Nerevarine in Morrowind. It is later revealed that she's Mara.
 * Martin Septim fuses with the divine essence of Akatosh to become his avatar for a short while.

As far as Skyrim is concerned, if one chooses to believe in the texts of The Alduin/Akatosh Dichotomy, Alduin is an aspect of Akatosh as well. Bethesda leaves to player to make the conclusion whether it is so.