In order to unlock Ultimate Weapon Anarchy, you must defeat the final boss, Cthulu in less than 5 minutes. This is not that hard depending on what difficulty you play and your use of Rampage Mode. Here is a Youtube video of this being done:
Eve and her comrades land on the surface to reclaim the extinct Earth and cross paths with a survivor named Adam. Eve is then led by Adam to the last surviving city, Xion, where she meets the elder of the town Orcal and is told many stories. In order to serve her mission to save Earth, Eve develops close relationships…