The whole thing kind of reminds me of Doctor Who a bit - with travelers from another time arriving in the midst of earthshaking changes and creepy alien influence, but having antagonists who aren't exactly evil, or even necessarily wrong.
The setting itself - between the mind-influencing "sky angels/demons" and the vast and eternal empire - reminds me of the world from the indie action-rpg game The Spirit Engine 2.
A choice quote: "As for elven language, I imagine they have tenses that are bizarre and long ranging (the Inevitable tense, the Inconceivable tense, etc.) with aspects handling the actual placement in time as normal folks think of it (by which I mean you need auxiliary verbs to establish if the inevitable has already come to pass or is yet to)."
Check out session 2; it's even more awesome.