Story
To protect the world from the impending invasion of the alien species known only as Evolutionary Invaders (EIs), the supranational organization called the Defense Organization aGainst Outer Objects (DOGOO) created special warriors through DNA manipulation called E-Gene Holders. These E-Gene Holders are the reincarnations of various historical figures. Using special weapons called AU spheres, E-Gene Holders can call forth AU weapons with an affinity to their assigned historical figure and use it against the invaders. Sio Ogura is one of them, being the reincarnation of Nobunaga Oda. However, her memories of her past life are limited only by dreams about the military past. Going on a school trip in Taiwan, Sio gets caught in the middle of a battle between the EIs and DOGOO's E-Gene Holders, alongside her classmate Kaoru Asao. When one of the E-Gene Holders, the reincarnation of Jack the Ripper, gets incapacitated and Kaoru ends up in danger when confronting an EI, Sio uses Jack's AU sphere to fully activate her E-Gene Holder status. She gains her AU weapon, a massive machine gun, and assists the other E-Gene Holders to put an end to the Taiwan invasion. After some reluctance, she joins DOGOO at Kaoru's behest.

(From Wikipedia)