Two things have always baffled me:
1. How long was it after the Battle of Red mountain till Nerevar's death (or murder)?
2. The relationship between Alandro and Vivec.

In Alandro's version, the Tribunal murdered Nerevar immediately following the Battle, and Azura cursed them for the murder. Then the Tribunal drove off Dagoth Ur, who tried to avenge Nerevar, and aquired the Tools and transformed themselves into gods.
In Vivec's version, Nerevar's death was never mentioned. He was wounded fighting Dumac, but it wasn't even implied that he died from that wound. It doesn't make sense to assume so, since he still had the strength to drive off Dagoth Ur thereafter. Ur wasn't killed. And it was only years later that Seht divined the mysteries of the Tools. Then the Tribunal made themselves gods and Azura cursed them for their foresworn oaths, not for the murder of Nerevar.

In the Doom Drum version from the Songs of Wulfharth, Nerevar struck down Dagoth ur and then took a mortal wound from Lorkhan.

So, among these three versions, only the Nordic one states that Dagoth Ur was killed. And IIRC, some information in the game (I don't remember exactly where) tells us that Ur was not only driven away but indeed was killed by Nerevar. It might be hard to believe that the Nordic retelling is the acurate one, but Alandro's story is apparently faulty, since in his story, Nerevar and Ur were loyal to each other until the end. Although a convenient excuse could be his blindness rendered during the Battle - so only the events after the Battle depicted by him are inaccurate. Personally, I think Vivec's version makes the most sense. It's detailed, with every action properly motivated, and leaves the space for Nerevar's murder or death from all kinds of possibilities. And it's quite meaningless to lie to Nerevarine since he was having words with Azura all the time.

Now for the second mystery. I assumed when I played Morrowind for the first time, that Alandro and Vivec didn't like each other, or they might even be in fact bitter enemies, since Alandro's story was endorsed by the dissident priests. But in C0DA they were best buddies. Actually it shouldn't have surprised me, because in the Trial of Vivec, it was already mentioned that Alandro was Vivec's "lover-liar". This is where my doubts begin.

In the Trial of Vivec, four items were procured. Three were used by Vivec against Azura in avenging the three memebers of the Tribunal. The fourth, a ringlet from Alandro's Wraithmail, was to be put in one's mouth, and "Almost immediately he shall feel heavy, yet light-headed. And a Voice will speak through him, carrying a simple yet beautiful yet powerful message from the greyness between times." When Harold put the ringlet into his mouth, the voice came "I am Alandro Sul... I am tired of this haggling. For three centuries after the battle I was the center of debate, for I opposed the Tribunal, the new leaders. Eventually, I knew I could no longer live among them, and so left. It has been a half and three millennia since the battle. Though I still miss my lord, I will no longer disrupt these proceedings with my words. I have said what I can; let another who is better known step forth. I yearn for rest. Let these rude conducts continue; what was done was done, and I will always remember that, Vehk, no matter what decision these foolish young ones come to. I will stay here no longer."

And then at the end of the Trial:
Vivec places ringlet in his mouth, and a Voice issues out.
"He was not born a god. His destiny did not lead him to this crime. He chose this path of his own free will. He stole the godhood and murdered the Hortator."
Vivec removes ringlet
Vivec: "VIVEC WROTE THIS"

I don't know how to nicely put the process of reasoning, so I'll just jump right to my conclusion. The Foul Murder was a lie, fabricated by the Tribunal and Alandro volunteered to be the false witness. Maybe Nerevar did fell from wounds, or even died of some very stupid reason, such as having held the Tools for too long. And they didn't want his death to mean nothing, so they invented the Foul Murder in the Dragon Break, and made him an avatar of Lorkhan. Because of this, the Nerevarine is also a Shezarrine, which is why he could steer Akulakhan into battle againt Numidium in Landfall: Day One.

Alandro disapproved of the Tribunal's leadership, but still, that doesn't mean he couldn't have been their friend and fellow conspirator. He loved Vivec and lied for him. He missed his lord Nerevar. He called the young ones, the ones intending to judge Vivec, foolish, and said to Vivec that he'll always remember (his testimony). That's why his voice "carrying a simple yet beautiful yet powerful message from the greyness between times" depicted the Foul Murder, the hidden message in the 36 Lessons, which was WRITTEN by Vivec.

Let's now take look at Vivec's confession, "Vehk the mortal did murder the Hortator. Vehk the God did not, and remains as written. And yet these two are the same being. And yet are not, save for one red moment." I assumed the first time I read this, that "Vehk the mortal" is the version of him in the original history, and "Vehk the God" is the one in the revised history - Vivec used the Dragon Break to overwrite his murder. But this assumption doesn't really make sense. If he wanted to wipe clean the old version, why would he admitt the two versions of him are one and the same at all time? And when was this "one red moment"? Was it the moment of the murder or the moment of his apotheosis? But if the murder was retrospective, it'd all make sense. The red moment is both the moment of the Tribunal's apotheosis and the moment of the Foul Murder, which was also Nerevar's apotheosis. At that moment, Vivec created and has since maintained his dualities, one of which is "mer Vel god" - mer or god or (mer and god) - the mortal Vehk that murdered Nerevar, the god Vehk that stays innocent, and the Vivec who's the same being of Vehk and Vehk.