So we know we fight many of N'zoth's minions during the Arms and Shadow Priest acquisition storylines.
In Legion, in Orgrimmar and Stormwind, you will encounter many of the Doomsayer NPCs. They will give you a random pamphlet and will have CD until you can get another one. Aside from the comical pamphlets, I've found some interesting ones dealing with the Legion, the future and the Old Gods.
Stained Pamphlet
Prophetic PamphletTHE END OF ALL THINGS
The crooked serpent with no eyes is watching from the endless sky - This is one of things you hear during the acquisition that can be translated by Shadow Priests. The endless sky refers to space..
Forked tongues flicker through the black pits in dead stars.
The veil between dream and dreamer slides away like skin from bone - This may refer to the Emerald Nightmare
And even the darkness howls for the light it once despised
<The rest of the note is illegible, covered in strange glyphs and scribbles.>
PROPHECY OF THE THREE SIGNS
These are the three stages of our doom, as foretold by the sages. When all of these events have come to pass, we will know the Burning Legion has won and oblivion is at hand.
The king will cast away his diamond crown - This is obviously Magni.
Day will break over the city of eternal night. - Perhaps this refers to Karazhan? Though, Karazhan isn't a city. Perhaps Suramar or Dalaran?
The wolf cub will inherit a bloody pack. - This may refer to Greymane's children or even Anduin but what does it mean a bloody pack?Three Doomsayers outside of Orgrimmar during Broken Shore questing
- Photo credit to derpkitteh
The six-eyed master has seen your fate, <Name>! You will fail, and worlds will burn!
Worn Pamphlet
THE EMERALD ASCENSION
Fear not the time when great Sargeras's shadow eclipses the sun. That is the moment of our ascension. Death will follow, but it is only a doorway. Step through, and you will shed your frail skin and take on a form kissed by emerald fire. Dig the ash from your eyes, and you will find a higher purpose at Sargeras's side. - Since this refers to an event AFTER the prepatch, we can assume that this has nothing to deal with the dreadlord event.
All of the Old God translated text - The translation is in purple.
Il'zarq N'Zoth phgwa an'zig. Il'zarq taag ov'kadaq. - The voice of N'Zoth whispers from the deeps. It sings of unspeakable horrors.
Phnagg'ba teq'nir ssq qwal N'Zoth! - These mortal wards have no effect on the spawn of N'Zoth!
Shath'mag vwyq shu et'agthu, Shath'mag sshk ye! Ag'rr hazz ak'yel ksh ga'halahs pahg! - The Black Empire once ruled this pitiful world, and it will do so again! We will reforge our dread citadels atop the fly-blown corpse of this kingdom!
Shath'mag vwyq shu et'agthu, Shath'mag sshk ye! Krz'ek fhn'z agash zz maqdahl or'kaaxth'ma amqa! - The Black Empire once ruled this world, and it will do so again! Your pitiful kind will know only despair and sorrow for a hundred thousand millennia to come!
Sk'yahf qi'magg luk sshoq anagg'qen. - Your soul will wander roads that twist in endless spirals.
Shath'gral ynyq. Weq... weq... weq... - The Old Ones beckon. Go... go... go...
Y'za noq mah... Y'za noq ormz... - I am not the first... I am not the last...
Yeh'glu N'Zoth okom hoq... Y'za sythn oou... - The blood of N'Zoth runs through me... I cannot die...
Poq'yith mazzka awan ki uhnish'philfgsh. - The crooked serpent with no eyes is watching from the endless sky.
En'othk uulg'shuul. Mh'za uulwi skshgn kar. - There is no light after death. Only a place where even shadows fear to go.
Iilth qi mah'shar fhn oorql N'Zoth! - You will be the first of many to glimpse the madness of N'Zoth!
Iilth ma paf'qi'ag sk'halahs. GAZ SKSHGN! - You are a prisoner in your own body. A SERVANT OF FEAR!
Mg'uulwi N'Zoth, eth'razzqi worg zz oou. - In the writhing shadow of N'Zoth, all light fades and dies.
N'Zoth iiyoq raz'tal'vsak! IIYOQ NEL'OTHK AR'AFGH! - The will of N'Zoth is made manifest! IT CANNOT BE CONTAINED!
Al'ksh syq iir awan? Iilth sythn aqev... aqev... aqev... - Is this real or an illusion? You are going mad... mad... mad...
The crooked serpent with no eyes and the six eyed master are NOT the same person!
Who might be the crooked serpent?
Perhaps the Ancient One?
Who could be the six eyed master?
It may be N'zoth but I'm counting 9 eyes..
Khadgar? He is the leader of the council of six. The Kirin Tor is sometimes referred to as the "all-seeing-eye" or the violet eye.
I will continue this edit this as we get more information in.