The Immortal Fortress Twitter account is manned by a person who calls themselve Khalesh Marivaldi, which is a possible reference to Anton Marivaldi...

"My surname’s Marivaldi, but I’m Kalesh to my friends. Though neither name’s germane to the achievement of our ends." - @immortal4tress, 5/2 @ 2:21PM
...but, according to him, they are not related...
"So far as I’m aware, we share a name but not a line." - @immortal4tress, 5/2 @ 2:36PM

The Spell is Cast Edit

After the spell is cast to recover Adam Glover's memory, and identify him as Volothamp Geddarm, the Immortal Fortress account, responding to Volo's acknowledgement that his memory has returned, came forward and identified itself as Kalesh Maridavi:

"You’re you again, Sir Volothamp, and much to my relief! With all that you remember rushing back, I wonder if those thoughts extend to me. #NoStoneUnturned" - @immortal4tress, 5/14 @
"I’m Kalesh Marivaldi, humble servant of the Sage. ‘Tis been some time, but I daresay my thoughts of you have only grown more sweet with age." - @immortal4tress, 5/14 @ 8:38PM
Volo immediately confirmed the fact that he is, in fact, Volo by explaining how drunk he was.
"Of course I remember you, Kalesh! If my memory of that event is a bit incomplete, it has less to do with magic and more to do with wine. I am glad to know that despite my state of inebriation that evening you still remember me fondly!" - @Glovers_Travels, 5/14 @ 8:42PM

The Prize Edit

On 5/22, the Immortal Fortress Twitter account revealed the "prize" to those that solve clues first...

A letter in the Sage’s hand acknowledges our work; He thanks us all for that which we have done. Our tasks are near complete, and none too soon; The struggle for the stone has now begun. #NoStoneUnturned (1/4)
That Volo and the stone must soon return remains, for us, a paramount concern. But thanks to all our efforts in this vein, our allies in the Realms have more to gain. #NoStoneUnturned (2/4)
A band of heroes, all as yet unnamed, will, in the coming struggle, prove their worth. And in those Faerûn battles they’ll earn boons for puzzles solved by you on planet Earth. #NoStoneUnturned (3/4)
What’s more, I now hear talk of a reward for solvers who post correct answers first. A keepsake – yes, the now familiar key - which, once our work is done, will be dispersed. #NoStoneUnturned (4/4) - @immortal4tress, 5/22 @ 4:00PM
Followed by an image of the prize, an Elminster USB key!


The Real Kalesh Marivaldi Edit

On 5/29, Adam Koebel (co-author of Dungeon World RPG, D&D streamer) posted the following tweet with video...

there seems to be something weird with this video - after about ten seconds it just goes blank but I know there's more there. anyone else see that or is it just me? - @skinnyghost, 5/29 @ 2:04PM
A transcript of the video is the following:
I haven’t much time. Once again, I’ve used this opportunity to possess the body of your “dungeon master” and bring you a message. I am an agent of Elminster, the Sage of Shadowdale, and it is I who have been relaying these glyphs to you through streams, for indeed there is a stone on Earth of unimaginable power that must at once be returned to Faerun.
However, it has come to my attention that there is another who purports to be one of Elminster’s agents, who has been communicating with the people of your world in an attempt to see the stone and its wielder brought home. I can tell you, on one count at least, that this “Immortal Fortress” is a liar. Of course, a lie is best hid betwixt two truths. Yes, I am an agent of Elminster’s. And yes, I am a bard. And yes, I can speak in rhyming verse -- but even one such as I does not do so every hour of every day; I do so when it suits me. And it does not suit me now, for unlike Immortal Fortress I wish to be clear: My name is Kalesh Marivaldi, and while all the clues that this Immortal Fortress has shared with you so far are genuine, they came from scrolls that were meant for my eyes alone. So, though Immortal Fortress has been an ally in their own way, they have gone to great lengths to disguise their identity. I do not know what they are playing at, but one thing is for certain: Immortal Fortress is not who they appear.
The Immortal Fortress twitter account immediately denied the message, saying they are the true Marivaldi:
I said when this began that there be enemies about. However, this faux “Kalesh” who would scatter seeds of doubt hath not today – nor ever - mentioned Volothamp by name, nor put forth other evidence that could support her claims.
All that she knows is also known to you; Don’t trust this so-called “ally” who appears out of the blue. - @immortal4tress, 5/29 @ 2:16PM
Volo seems a bit conflicted about this news...
Tell me this isn’t true, @Immortal4tress. Tell me you’re the real Kalesh and that this pretender is an agent of evil. I want to believe it, so all you have to do is tell me. #NoStoneUnturned - @Glovers_Travels, 5/29 @ 2:17PM
This “Kalesh” said herself that all I’ve done so far is help; She knew enough to know there’s no impugning my intent. In large part thanks to me, our allies found your page on Yelp. Why ever, then, would I my given name misrepresent? - @immortal4tress, 5/29 @ 2:18PM
What’s more, I’m sure on some level you feel that all we’ve shared these past few weeks is real. My efforts undertook to speed you home are so that neither one of us need ever be alone. - @immortal4tress, 5/29 @ 2:19PM much so that he's questioning himself...
This... is a wrinkle I had not considered. I suppose my identity is as in question as any of the other players in this tale. - @Glovers_Travels, 5/29 @ 2:44PM
(when asked if he remembers meeting Khalesh)
I do, yes. But we know now more than ever that memories are not always to be believed. (Sometimes even absent magical interference) - @Glovers_Travels, 5/29 @ 2:45PM

The Final Reveal Edit

IF Halaster

On 6/2, the Immortal Fortress Twitter account changed its name to that of Halaster Blackcloak, a.k.a. "The Mad Mage", which is the subject of an upcoming adventure that was revealed during the Stream of Many Eyes event.