Magnus was the architect of convention and used Lorkhan as inspiration/advice in the creation of Nirn.

When all is said is done, Magnus is safe in Aetherius, Lorkhan is dead but not(also maybe not dead if Talos is in place. More below), and Auriel and the rest of Aedra are every severely limited in power ( some say dead). My question is that could have Magnus been in on the trick that the Aedra weren't? Could he have known the consequences of their sacrifices? All of a sudden he's the big fish in Aetherius.

Side note: in SI, the CoC mantled sheo until he became him completely. As in there is nothing left of CoC and just Sheo. Why isn't this the case with Talos/Lorkhan? Why isn't Lorkhan alive and well because of the Talos oversoul?