I got the first three volumes of Knights of Sidonia (couldn't help but think of Muse's Knights of Cydonia) a while back and have finally come around to reading them. It's a space opera Manga about a self-sustaining colossal ship Sidonia and its mecha fighters that battle against an alien, shape-shifting species dead set on destroying humans.
This first volume is like many first volumes. Some things are promising but a large part of it is dumping characters and information about the world on you as you try to figure out what will become important later. The main character at this point was this typical nobody with a mysterious past that I'm sure will become important at some point.