GUNNM: Last Order

Gally loses consciousness in a battle with Nova. When she awakes, she finds herself in Zalem. However, Zalem, which was thought to be a technological paradise, has been devastated and turned into a hell filled with death and violence. In order to rescue her close friend Lou, Gally wanders through Zalem. A new battle begins in Japan's world-class science fiction epic “GUNNM”!
(Source: Kodansha, translated)
Note: This is the sequel to the Battle Angel Alita/GUNNM manga, ignoring the original ending.