Okay so here's what I believe happened to Efrideet. In the new rise of Iron, artifacts are tokens of lost Iron Lords, but Efrideet doesn't have one. Many people believe that this is because she simply vanished, but what if Efrideet didn't have an Iron Lord token because she isn't considered an Iron lord anymore? What if she somehow fell from the ranks and became unworthy of the title. In the live stream we were told that SIVA needs a host to control it, and that it's power is only as powerful as its host. Now we know that the fallen couldn't have been responsible for the SIVA outbreak back in the time of the original Iron Lords because of one simple fact. That eight out of ten Iron Lords are dead. It takes a power possessed only by the darkness to steal a guardians light and actually kill them. But a guardian having this ability is not unheard of. (Dredgen Yor stealing Panahin's light in the crucible with thorn and killing him) Now here's my theory: Efrideet turned against the guardians and the light during their prime for an unknown reason. Finding the power of SIVA she intended to use it against the guardians, but the Iron Lords intervened being protectors and also feeling guilty for their fallen comrade. They fought and fought, most of them died but in the end they sealed her away. Yes they sealed [i]her[/i] away, SIVA is powerless without a host and her addiction to the power of the machine was her downfall. She refused to escape without the technology allowing the Iron Lords to quarantine the SIVA. There she stayed for however much time has passed between then and present time in destiny. After the house of devils lost their Kell to Saint-14, Their Archon priest, and Sepiks Prime. They stumbled upon SIVA and by extension Efrideet. As the majority of us know the Eliksni/Falle have always worshipped machines and since Efrideet has become one with the machine having it under control she would have been seen as a God to them. It's safe to assume that she was immediately made their Kell as it is not unheard of for an outsider to take the throne. (Queen of the reef Mara Sov) As Variks states in "The Wolves of Mars" quest line "The Fallen cannot be this organized with no kell". And so with the power of SIVA and her newfound army she set out to finish what she had started. And so I believe she will be the final boss in the raid and we will receive her token as a prize for finishing the raid. How she may die I am unsure, perhaps she is so entangled with SIVA that shutting down the machine itself may kill her. And although she still may have light left over she may have abandoned her ghost as Dredgen Yor did in "Ghost Fragment: thorn 3". I believe we will be given her token because a guardian lost to the darkness is remembered as he/she was, as hinted at by Dredgen Yor when saying "If you do not forget that man, you will taint his legacy". And there you have it, let me know what you think.