I'm thinking that Rasputin is now the Speaker, and considering we can't see any of the speakers body it sounds plausible. Rasputin sacrificed millions of human souls for light so that he could stop the darkness? The speaker says the darkness cannot be stopped again? I think the speaker knows that there just isn't enough of humanity left to sacrifice in order to push it back again. The speaker knows everything, but instead won't tell us the story. Would it blow his cover? It also sounds like Rasputin once had all of the powers of the current guardians with the aurora knife, fires of singularity and sweat as earthquakes. Sounds like Rasputin is simply pretty badass. If we do restore the traveler and it isn't the good that we think it is? Who's to say it won't just take the light it gave us back ? We're just an undead zombie army of "light" what other purpose do we serve after the traveler is brought back? I'm thinking it's going to take our light back for more power.