On Lorkhan: A Elder Scrolls theory

Humans

Humans views of Lorkhan are a bit more diverse compared to the elves.

Nords have the most famous version, called Shor.In ancient Atmoran legends he's a mighty warrior king who led them to victory after victory from their Altmer oppressors. Until he was finally slain by the elven gods and had his heart ripped out.

From there its basically norse mythology, he sits on his throne in Sovngarde where the souls of great warriors go after death. They feast and have a jolly good time until the Last war (Elder Scrolls Ragnarok I suppose) where he will lead them again.

We see this ourselves in Skyrim but Shor's throne sits empty, which still rages hot debates among the lore community.

And since we, the last dragonborn, can sit in it many believe we, the player, actually is Shor, or at least an avatar of him. In the lore there's something called a shezzarine, an aspect of the missing god(aka Lorkhan). Another example of it is Pelinal Whitestrake, the mad knight who slaughtered Ayleid elves during the nedes war for freedom. So could we really be a shezzarrine, sent to stop Alduin?

There is a vague legend in nord lore where Orkey, the Atmoran snake god and enemy, cursed the ancient Atmorans. Their lifespan was reduced to merely six years, Shor lifted this curse and threw it onto other races, mostly the orcs (cause no one likes them for some reason)

Also Orkey apparently summoned Alduin that slaughtered most nords, reducing them down to merely 6. King Wulfrath pleaded to Shor for help, and Shor then battled Alduin on the spirit plain and slew him. Does this not remind you of the Skyrim main campaign? So there is very good reason to suspect the Last Dragonborn of being a shezzarrine, arriving just in time to take out his old enemy like in the old legend.

This story is highly unlikely to have happened though, since we DID see the ancient dragonborn defeating Alduin but its a interesting story nonetheless. (also six nords only? There is no recovering from that, the elves would have finished them off.)

However when we are in Sovngarde it should be noted we are alive, not dead, when entering. Of course we can see the spirits of the fallen there, and they do speak of Shor but mostly just in mentioning that he's ordered them to stay indoors and not fight Alduin. There's no mentioning of him being actually gone, nothing about that he left to do something. And the spirits do not speak to the player as if he/she was Shor. We're just a great hero to them, there to stop Alduin.

So there's also strong evidence against the shezzarrine theory, maybe we just can't see Shor cause we're alive? Or maybe he did leave to do something behind the scenes and he will return shortly after we go back to the living? Perhaps the spirits didn't mention that part cause its normal? That Shor leaves to do god business and don't always stay in Sovngarde constantly, we don't stay long after all. The short time in Sovngarde is hardly gonna teach us much of their normal routine there. (besides the endless food and drink which does sound good)

All of these are just my random thoughts, I have next to nothing to back it up with.

BUT it could also be possible that the souls there just doesn't know. After all it would be in Shor's best interest to not tell them what he was up to. Lorkhan/Shor is often called the trickster god, and on the carvings in nordic burials he's depicted as a fox. And what are foxes but symbols of trickery and cunning? If he saw Alduin return to Mundus it would not be out of character to swiftly come up with a plan. To tell everyone to stay put as he rose from his throne and marched out, putting his god essence into a womb of a unknown mortal and be born a shezzarrine at just the right time, to arrive at just the right place to stop Alduin, to take him by surprise. If he did tell someone what he was up to then it could get back to Alduin, giving the son of Akatosh a chance to intervene in Shor's plan.