I was just wondering, could a powerful character like the Nerevarine or the Dragonborn resurrect someone. And I don't mean make them into a zombie or a thrall. I mean fully resurrect someone, possibly even remake them somehow. Forbidden Knowladge might give the Dragonborn the powers to do incredible things and dragons can be resurrected fully. The closest thing we have to a fully resurrected person would be a Lich right now. For this let's say we want to resurrect someone like Almalexia. If we had her soul and her body, could we possibly resurrect her, perhaps with sacrifice or some mystical artifact we haven't seen before. My question is: could it be done and has it been done?

In theory it is possible but practically it isn't. Dragons can be resurrect if their soul isn't drained because their soul is immortal and goes nowhere. Mortal soul goes to afterlife (whether that be a daedric realm, Sovngard, the Void, Soulcairn or something else.) In order to resurrect mortal we need his soul but not in after life or not in soulgem (we couldn't get it out without loosing it to Ideal Masters.) So if someone figures how to force a mortal soul to stay on Mundus we could be able to resurrect that one if we'd be powerful enough. But a mortal being powerful enough for it? I doubt that would ever happen.

There was an attempt to resurrect the Wolf Queen in Skyrim, who had been dead for centuries. Though it was an attempt by a whole group of (presumably skilled) necromancers, not a single individual.

Yes, that has been tried some times in Tamriels history, but I have never heard anyone to success with it. In Redguard they tried to do that for Crown prince A'tor with his soul in soulgem but the soul enchanted his sword instead of going back into his body.

Didn't Wulfharth come back to life once or twice? Or was he more of a ghost? On that topic we have ghosts wondering about... some of them not entirely insane either. Maybe you could put that ghost into a body?

Wulfharth was killed, but mages who practiced the Way of the Voice sung Shor's back to life and rebuilt his body from the ashes of Wulfharth. Shor the possessed Wulfharth's body. So in a way, a soul could be sent brought back using the voice or some powerful magic. The problem would be the body. Possessing a body is all well and good, but creating a new body would be more tricky. The reason I pointed out Almalexia was because she had a connection to the Heart of Lorkhan, as did the other members of the Tribunal and Dagoth Ur. Wulfharth also had a connection to Shor, who's heart is the Heart of Lorkhan. Not just anyone can be resurrected. But people with a connection to the Mission God could be resurrected, dough only by a group of highly skilled necromancers.