I, once again have a theory regarding the story of destiny!!! That's right, sceptics, grab your pitch forks and torches!! You know who you are. Okay on with my theory I believe Eris Mourn has a Worm (or Wyum, however it's spelt). Who's Worm? And from where? I believe Eris Mourn was given a Worm whilst she and thousands of fellow guardians lunched their raid on the moon, after they were all killed or lost within the Bowles of the Hellmouth. I think, sometime during the attack, Eris was, like many guardians, defeated, her light and ghost were gone and she was soon to die. However, we know Eris was very close comrades with Toland the Shattered, perhaps, this close partnership lead to Eris learning a great deal of the darkness and the Hives use of "magic" and "rituals". I believe, in her desperation, she practiced the rituals of the Hive, learning through trail and error as well as observing Hive wizards, using her Light as a catalyst for these powers. Perhaps, I believe anyway, she used both her light and Crota's throne world, as means of trying to transport herself out. We know Eris has knowledge of Hive magic as seen in one of the Taken king missions in which Eris literally teleports us out of Crota's hive world. How else would she have this knowledge if she didn't use the same method to escape. However I believe Eris didn't completely escape, I theorize that Eris left Crota's throne world and found Sava'thun's Throne World, where the two made an unlike deal. Sava'thun would, over the course of years, (perhaps even hundreds of years, as we have no way of knowing how time in a Hive netherworld works or even if it exists at all) teach Eris the secrets to the hive, their secrets, history and their connection to the darkness. And maybe even the traveler... However there is only so much Eris can do with her limited Light and by extension of their deal, She would also need to consume a Worm larvae. Maybe Sava'thum's Worm Larvae had grown enough to begin to bare its own Worm larvae, and Eris mourn was forced to consume it to further her knowledge and connection to the Hive. As for what Sava'thum would gain in return? She would gain a second host and second means for her Larvae to gain tribute. The larvae however caused various abnormalities in Eris, such as her third eye and exceptional knowledge of Hive magic. However she would also have to conspire with the Vanguard to lead an assault on Crota's throne world, knowing killing Crota would enrage Orxy and force him/her to launch a deadly attack on the Last City. At the same time, Eris would teach guardians the secrets to killing the Taken and Orxy himself, all for the purpose of Sava'thum taking the throne of Hive God for herself. Perhaps she sees Orxy as a pathetic King, seeing as he would forget his mission of destruction, simply to average his dead son. Sympathy, Love, Regret, all emotions Orxy is guilty of. Emotions that are products and constructs of the Light, as originally, the three sisters were only motivated by anger and revenge as well as pride to a certain degree. This would insult Sava'thum, and thus seeing herself as a far more worthy King. As for Eris mourn now and where she is now? I believe Eris mourn is slowly starting to come to grips with her new powers and, like Saint-14 has left in search of Osiris, seeing him as the rightful leader of the tower and guardians. Seeing the Speakers limited world view and almost selfish way of thinking, Eris mourn wishes to, just as she helped Sava'thum usurp Orxy, so too would she help Osiris usurp the Speaker. That is where I believe she is now, helping the Vex empowered guardian with her deadly mastery of Hive dark magic. This is my Eris mourn theory and I hope you all found it enjoyable and somewhat entertaining. Please feel free to share your opinion in the comments as well as your own theories. (Also I know Destiny is coming to an end and in D2 they will change the very nature of the Light and the Darkness but I mostly just make these theories for people to read and enjoy and to share my personal thoughts of the current state of destiny)