GourdHonestly I'm kind of glad they didn't give Grace O'Connor a motive besides being a mad scientist who wants to be god queen of the galaxy because it'd likely have resulted in mecha anime arguments about hope and despair, while the entire plot coming out of nowhere in the second to last episode like it does as a thing some lady is doing for some reason is much funnier and doesn't interfere in what the show is actually about.
Last episode is basically an incredible twenty minute AMV.