I'm not sure if this has been brought up before, but on my read through of the trilogy, I thought that there were several parallels between the books and the show Tengen Toppa Gurren Lagann.
For instance, you have an all-powerful king/emperor who has maintained power since time immemorial. Said king has relegated humanity (or parts of it) to being second-class citizens who can never rise above their position.
Then, one of these humans decides to break free, and change his world. He recruits a young child who has superhuman powers that he/she should not have had. They meet several others (Stretching a little bit) who join their crusade, and they attempt to overthrow their oppressor.
Once they do, the oppressor, with his final breaths, tells them that they have doomed themselves. They don't know what to make of this. Life goes on.
Beyond that, the stories diverge a bit, but the crux of it now is that their actions interfered with a policy that had been thousands of years in the running, and which was the sole reason for their continued existence. Now, they'd need to deal with what they unleashed.
There are more, but I didn't want to go too in-depth into the stories.
