>>280834218
It's hard not to just assume its Dawn, it's a consistent theme of the series, with our current major villains are defined by either letting the world turn to nothingness or covering it in darkness, and it was so important that it has stuck around in every single pilot for the series.

My assumption based on the Harley text is that there's some kind of cycle that repeats and Imu has acted as a Wedge preventing it from continuing for the past few hundred years, with the goal of just letting everything end.