Now, before anyone goes on saying this should be placed in fanfiction, I'd like to start a discourse on another interpretation of these events.
Don't forget that these individuals venerate Boethia and Mephala (not exclusively, mind you, but I choose these two to make an example). The Web Spinner and the Prince of Plots both encourage betrayal in their own way. Would their worshipers not consider betrayal to be a holy thing? Perhaps Nerevar intended to betrayed by his friends and in doing so betrayed them as well. He betrayed his intention for the Tools of Kagrenac not to be used, damned the Tribunal to demi-godhood and damned himself to death.
Transcribed are the words no Tribunal priest will read and no Dunmer will hear. It is the last testament of Indoril Nerevar, hidden by and from those he loved most. Though this account will never surface, it is important to know that it was so.
The sun was high, obscured, and just visible behind a veil of red ash that circled the mountain.
Four figures made their way up, heads bowed low in anticipation.
Before reaching the mount of the summit, Vehk stopped ash upon his face and hands.
“Beloved of my house and my words and our people, must we continue? Are you so set in this, your grim task?
“I am” replied Nerevar
Vehk nodded and proceeded alone.
Thus approached Seht, ash upon his mask and mantle, and he asked
“Beloved of my house, my thoughts and our people, is there no other way? Do you truly believe it best, your grim task?”
“I do” replied Nerevar
Vehk knew this was true, and proceeded alone.
Next approached Almalexia, ash upon her heart and brow
“Beloved of my house, my blade, and our people, bid me adjourn and I will. Or will you proceed in this, your grim task?”
“I shall.” replied Nerevar
Almalexia’s face screwed to great anger, but stilled, and she proceeded alone
Lord Indoril watched as the three climbed. His heart was heavy with purpose, but his soul was light knowing.
With one look back to the realm of Resdayn, veiled by ash, he proceeded with those who were his beloved.
When the three reached the summit, Nerevar approached and spoke
“Beloved of my self, three gifts you have for me, thus three gifts I give to you. So shall you array them amongst yourselves as you see fit.
I bestow Wraithguard, shield of soul, to protect you from folly
I bestow Sunder, mallet of strength, to strike mystery
I bestow Keening, blade of truth, to derive knowing
May you use these gifts as you intend, for I love you.”
The Three accepted their gifts in silence, but it was Seht who spoke amongst them.
“Though mask and mantle obscure my face, already it is shorn with grief. “
“Aye, and do my feet ache with penance.” spoke Vehk
“Your grim task wounds us, Nerevar Beloved” spoke Almalexia
On hearing this did Nerevar’s unbroken peace turn to holy wrath
“You know not of what you speak, for it is my face that is shorn, it is my feet that ache, and it is I who is wounded.
This grim task is not mine, for I have already known. It I yours and for you I have wept. Speak not of sorrow, this task must be done”
The three bowed in tribunal of acceptance for their fate, and proceeded to lay down their gifts.
Nerevar lit Almalexia’s poison candles
Nerevar donned Seht’s poison robes
Nerevar spoked Vehk’s poison incantations
“If you truly love that which is your beloved, then you must be willing to betray them”
Sotha Sil wept as Nerevar’s face was shorn and artifice hid his tears
Vivec cried out in bereavement as Nerevar’s chest was wounded and ashen veil hid his fear
Alamalexia severed Nerevar’s feet, cradled them lovingly and madness hid her anger
And all is as it was, and all became as is should be.