I just thought..

the Ebony warrior says only you can send him to Sovngarde, and when slain says "at last.. Sovngarde..."

Then why do we not see him when we enter Sovngarde? theoretically, he would be much better help against Alduin then the three tongues that help us...

*Omm Nom Nom*

Probably just because the DLCs don't really interact with the vanilla game that much. There's things added here and there, but you don't get to talk to

[Dragonborn Spoiler]

Probably something Bethesda forgot to implement, but it would have been really cool.

Probably because most people are long done the main quest by the time the Ebony Warrior shows up.

That and it might be hard to code something from DLC into a quest like Sovngarde..

Because he's a Redguard. Others think he's an aspect of Shor or something.

I like to think Tsun/Zenithar. But there's always the option that he's just an incredibly powerful easter egg meant to signal the end of the road.

this reason!

Most likely a Nordic father and Redguard mother. Family name, ancestral rights and beliefs of the father's side. Appearance of the mother's side.

Some would want you to explain his height, godly skills, and his ability to shout.

You're right, it's better than the three pathetic losers who bow out after one hit from Alduin.

true. he can shout, and other then the player, the only characters we encounter that can shout are Nords..

I believe in the theory that he is meant to be a Nord, but they made him a Redguard so he would have the racials required to make the fight more challenging..

If his father was a Nord it would make him ethnically Nord by household yet in TES characters take the racial appearance of their mother.

A bit like Hjalti Early-beard (later to take on the name of Tiber Septim) which is obviously a pure Nordic name yet pictures of him make him look more Breton suggesting his mother was possibly a Breton.

I can make any race in the game into the Ebony Warrior.

He took a dive in the waterfall and is swimming down there. Probably the reason why you didn't see him.

Just because he thinks he's going to Sovngarde doesn't mean he will, considering he's redguard. But I don't think he's a mortal anyway. I believe what MerchantMudCrab said. That or Ebonarm, but Tsun would make more sense. Same height, or rather close, uses thu'um and no one but the grey beards or ulfric could have taught him. Thats the biggest clue right there. And Tsun, or "Zenithar" was a redguard in morrowind.

All I know is he is badass but not as badass as Black Dynamite.

No, but Cyrus is.

This would be the reason right here. DLC/expansions for The Elder Scrolls titles are always (with the exception of minor add-ons) designed with the mindset that most people have already completed the MQ's of the base game and any previous DLC/expansions, and are always designed as an extension to that. For instance, the way dialogue was written for Bloodmoon assumed that the player had already completed Tribunal's MQ, and likewise, Tribunal's MQ will make no sense whatsoever if you haven't already completed Morrowind's original MQ.

Oblivion and Skyrim share this to a lesser degree, but actually accounted for certain player actions like how they handled dialogue for Miraak depending on what you've done so far in the base MQ and how you get different dialogue for Sheogorath's Daedra Quest in Oblivion depending on how far you are in SI's MQ, but for the most part, DLC is treated as "Beyond Endgame" content, as it rightly should be.

You don't see the countless adventurers or other random people who die either. They didn't add everyone into Sovngarde.