I thought he was also a Monk.

He founded the order of the Greybeards but originally he wasn't a monk. He became one later, but initially he was a warrior.

true, now that I dug deeper into his background. I found that his skills match that of a Warrior according to UESP.

I'm just trying to find an explanation to the Dragon Soul obtained at the altar and its the only thing I could think of.

Peolpe also wonder about the daedric letters on his grave but that has no answer as well.

you guys said half races couldn't exist in Elder Scrolls Lore, then  what is Umaril the Unfeathered then. According to ShoddyCast Lore video on Meridia, he is a half Ayleid and Half Auroran.

The thing is that in Oblivion he looked like really big Auroran. Phil might know more about him than me, but as I said before: There are ni half-races as we know them from other fantasies. Children don't share mixed physical appearance of both their parents. But they can be dubbed Half-something. Especialy when you want to explain both halves. Think about this way. If Aldmer male bangs Nord/Nede woman, they will have a child that looks human but has affinity to magicka like Aldmer. Thus Breton is born. I'm really oversimplifying it here. :D But...Now that I think of it. We know what happens when races of Tamriel interbreed. I can't say what happens when you add Daedric spark to that equation if you get what I mean.

since he was her Champion. maybe Meridia made him.?

Can´t say, mate. "Demi-gods" of Tamriel never were part of my porfolio. 

The only source commenting on Umaril's lineage is The Song of Pelinal, Vol 3 where it states he had an Ayleid mother and a divine father.

It's also stated he made a pact with Meridia to give him immortality. In game, he looks very similar to the Aurorans, but we've only seen his armor and it isn't too surprising to me with his connection to Meridia.

There's nothing stating who or what his father is.