Like he said, the beginning of the anime would fool you into thinking that this is a light, school-life based anime. Things twist around as the story's main protagonist, below average-wallflower type-military otaku-highschooler, Shio Ogura is caught in the middle of an invasion by evolutionary alien life-forms. She then becomes aware that she is a host of the E-Gene, the essence of outstanding individuals from history infused to a certain host of a future generation. The E-Gene also enhances the abilities of the host and materializes their weapon of choice.
The main concept in the series is about famous and outstanding individuals from world history that are reincarnated into hosts in the present day, with enhanced abilites and weapons that are associated with what that historical figure is known for. For example, Jack the Ripper's E-gene host has a large slasher blade, or Isaac Newton's host has a boot that amplifies or induces gravitational forces, etc.
It has an almost similar concept as Ikkitousen (with their megatamas and sharing the same fate and skill of the famous figures from the "Romance of the Three Kingdoms" saga), mecha designs that reminds me of Metroid/ Bubblegum Crisis, and the fight scenes of Ninja Scroll all mashed up nicely, together with a kick-ass opening theme "Respect for the Dead Men" by Pay Money to My Pain, packed in this series that is guaranteed to drag you into their world.