One of the running narrative themes for the main series is Immorality , which also became the key character theme and was expressed through their personalities and actions . The second game also focused on themes of war and death . The theme for the world of '' Drakengard 3 '' , as described by composer Keiichi Okabe , is " the sense of contrast " . Multiple anime series have influenced the series ' characters over the years , including '' Neon Genesis Evangelion '' , '' Sister Princess '' and '' Puella Magi Madoka Magica '' . The series writer , Sawako Natori , drew inspiration for her writing from shōnen manga . The original game world was designed around Celtic and Norse myths , together with Japanese-style revisionism . The team for the original game were influenced by Asian epic movies and western action-adventure films such as the 1999 remake of '' The Mummy '' and '' Dragonheart '' . While developing '' Nier '' , the team drew inspiration from the '' God of War '' series , while the narrative structure was inspired by the September 11 attacks and the War on Terror . The central theme of '' Nier : Automata '' is struggling out of a bad situation , defined by the game 's staff using the Japanese word " agaku "
September 11 attacks
September 11 attacks
Drakengard