Perhaps others had already noticed this and I’m just blind, but after Zenos gives permission to take more aether from a source “closer to home,” Fandaniel turns around and, staring up at the tower, yells
The time has come to fulfill
your hearts desire! My hearts desire! To relieve those wretched creatures of their meaningless existence!
My initial interpretation was that he was directing this statement to Zenos, but what if he wasn’t? The camera, Fandaniels direction, all seems focused on the tower. The dialogue in other languages also points to this. If all that is correct, then that does narrow down who it could be, as I don’t think many characters would wish to “relieve those wretched creatures of the meaningless existence.” Certainly couldn’t imagine it being Varis. Would an unsundered fit? Emets voice is the narrator in the trailer right?