Alright, so you wanna know why I think that Eriana-3 and Eris Morn are the same character? You all say they're totally separate characters, but I'd like the community to find me one instance where any character other than Toland or Eris refers to Eriana-3. The following contains spoilers about Fight Club, Slaughterhouse-Five, and Mr. Robot. [spoiler] In the book Slaughterhouse-Five by Kurt Vonnegut, the TV show Mr. Robot produced by Sam Esmail, and the book Fight Club by Chuck Palahniuk, the characters deal with something called dissociative identity disorder. It's a coping mechanism for undergoing a traumatic experience. In Slaughterhouse-Five, the doctors tell Billy Pilgrim (the main character) that his traumatic experience came from being pushed thrown into the water by his dad, but it's later revealed that Billy's true trauma was the Dresden Fire Bombing, an event where thousands of people were killed and few survivors were left, including Billy. In Mr. Robot, Elliot, counselor originally tells him that his trauma is being pushed out a window by his dad, but it's later revealed that his dad died from cancer caused by radiation poisoning at his job. In Fight Club, the trauma is unclear, but throughout the whole book, the unnamed narrator talks about his best friend Tyler Durden. In all three media, there are three common roles: the narrator, the fictional friend with a desirable trait, and the observer. In Fight Club, there's the unnamed narrator, there's Tyler Durden, and there's what the narrator refers to as you. In Mr. Robot, there's Elliot the narrator, there's Mr. Robot (who is his dead father), and, again, there's you. In Slaughterhouse-Five, the narrator isn't Billy Pilgrim, it's Vonnegut narrating Billy's life, then there's the character with the desirable trait Billy Pilgrim, but this time, the observer is assumed to be you. In Eris Morn's story, the traumatic event is her whole fireteam dying, then her three roles are taken by Eris as the narrator, Eriana-3 as the friend (because Eriana-3 is an Exo, Eris hopes that her transformation would have been less... painful), and the observer, who this time is occupied by Toland. Toland the Shattered and Eris Morn are not credible sources on the Crota incident because Toland is mentally broken and Eris... well, she's Eris, and organic minds do funny things to deal with trauma. [/spoiler] In the end, I don't give a crap about what the community says about my theory, but I don't think that what we know about the Crota incident is the full truth.

Eriana-3 is an Exo. Eris is obviously of Awoken origin. Eris is a Hunter. Luke Smith has confirmed that fact. Mara Sov is still alive. I don't feel like looking up the card name, but it follows her brother as he wakes up on Mars after the attack. He calms himself down and can somewhat feel her presence. Would be impossible if Mara was dead. Eris is obviously talking to the Queen of the Reef as this whole attack was planned by Eris and Mara. Literally in the Grimoire. Eris' part was to get the Guardian to capitalize on the main attack and get on to the Dreadnaught. Most of these "theories" about Eris ignore basic information easily found within the Grimoire.

So many holes in this theory

Ohh im a spooky Hive God!

I read through the full text and i can say with firm confidence that this theory is wrong. It seems to just casually gloss over Eriana-3 clearly being an exo made entirely of mechanical parts but somehow forming a clearly organic being. I understand space magic is a thing in this universe but logically speaking why waste the effort changing an exo into an organic when you could've just possessed a different member of the team that was organic? Also this theory clearly just ignores the fact that Ikora Rey knew Eris [b][u]before[/u][/b] they went to the moon to kill Crota. Hell Ikora is a member of the Hidden with Eris. Like Christ do you people even read the lore before posting your crack pot theories? Sure Eris is weird and clearly a shady individual but her being a hive god? Yeah sure, and Rahool is secretly the Awoken equivalent of Satan.

One thing, Eriana-3 is an EXO

Terrible

So a couple things First and foremost, Eris and Eriana-3 are two different species (Awoken and Exo, respectively). While the Hive could have used Space Magic/Ontological powers to transform Eriana-3 into an organic, there's no evidence to suggest that they did, or even would have any reason to. In fact, it would be far simpler to just corrupt Eris and be done with it. Transforming a robot into an organic being offers no obvious benefit to the Hive and so it's unlikely they'd perform such an action. Second, you question towards the end of your theory whether or not Eriana's actually an Exo ("Is Eriana an Exo at all?") Simply put, yes. Yes she is, and there's ample evidence to support this. The first piece of evidence you've already seen in the comments: her name. In Destiny, Exos bear a number after their name indicating how many times they've had their memories wiped (I can't remember the specific grimoire card/Bungie confirmation for this off the top of my head, but I think that's a well established fact and so I won't go into depth there). If Eriana wasn't an Exo, breaking a well established naming convention wouldn't make sense from a developer standpoint as it would confuse players, and it would be odd for other characters in the actual Destiny universe to refer to an organic with the naming convention of an Exo, especially when the number "3" doesn't bear any special significance to Eriana, at least, not in the current lore. For further evidence that Eriana is an Exo, in the "Blades of Crota" grimoire card, Vell Tarlow notes that calling a world carver a Knight would be an "understatement" akin to calling Eriana-3 a "Tin Can." Complete the analogy: knights are to world carvers as tin cans are to... Robots, or Exos in this context. Calling an organic being a tin can makes no sense, even in deliberate understatement, as organic beings aren't comprised of metal like a can, while referring to an Exo as a tin can in deliberate understatement would be logical for the same reason. Also, Toland refers to Eriana as a "rattling machine" in the Omnigul grimoire card, also indicating her being an Exo. Thirdly, your analysis of the Fist of Crota grimoire card is flawed. You took the quote "Eris and Eriana said the Blades rose first and slaughtered our brothers and sisters. If the one who leads their charge is within reach, I mean to end him- to end them all," and noted that it was odd that they were mentioned so closely together, and that this closeness suggests that the two are the same. However, note the Speaker of the quote, Vell Tarlow, died when they first tried to assault Crota's throne world ("At the doors to the temple he fell the last time" -Hive 2). If Eriana turned into Eris as you claim, then Tarlowe wouldn't have identified Eris at all because she wouldn't have existed yet. You also stated that certain fallacies in the lore could be Nokris "interfering with the recording, changing the way things were recorded," but I don't see any evidence for this actually occurring. In fact, we've only just learned of Nokris' existence in TTK, nearly a year after most of the lore surrounding Eriana/Eris was released, and it would be odd for Eris' entire existence to be based off of a Hive god that, from the community's perspective, didn't exist until nearly a year after she (Eris) was introduced. As for Eriana being able to hear the voices in her head like Eris, you yourself noted that the Worms (and therefore the Hive) can affect the minds of machines, as shown in Verse 4:9 of the Book of Sorrows (since you already gave the full quote, I won't bother reposting it again but feel free to ask for more clarification). If the worms can affect Vex hardware, there's no reason to believe they couldn't affect the hardware of an Exo and cause Eriana to hear voices like Eris. Moving on, you noted that Eris is "inexplicably powerful," as evidenced by her teleporting your guardian out of the fray during the "Last Rites" story mission, and how unusual it was that she must have possessed this power when trapped by the Hive but apparently was unable to use it to escape, and that this evidences a motive to stay among the Hive and pursue some goal other than escape. This argument can easily be put to rest with Bungie's favorite lore term: Space Magic! Seriously though, the exact nature of the spell she used to pull us out is unknown. It could be it only works on Guardians, or can be used to transport other objects but not not the caster. Eris could have required something from the outside world to cast the spell (sure would explain why she wanted all those eyes from us in that one TDB side quest). It could also be that Eris didn't have a safe spot to teleport herself to when she was roaming around in the Hive world, what with all of Crota's various body parts and aspects running around. In short, there are many more plausible explanations for Eris not using the spell to escape than her secretly being an Exo turned god turned Ex-guardian. I have a couple more points I'd like to make, but it's 3:00 AM where I am right now, so maybe I'll add those on later. Goodnight to you, OP.

An Exo is a robot. Mara Sov is not dead (Bungie confirmed). The Vex are not actually robots. Nokris was Crota's brother, but failed to conquer a world at the right age like Crota, and was executed by Oryx. So no, Eris Morn is not Eriana.