The screenwriter, Andrea Materia, is a long-time fan and historian of comic books, especially Japanese manga. So he filled the script with lots of manga references. Most of the Demons gang members, for example, are named after manga/anime characters. Kite takes her codename from the famed action/x-rated movie, Berserk from the namesake hero by Kentaro Miura, Conan spoofs "Meitantei Conan" by Gosho Aoyama and finally Spike is a homage to Spike Spiegel (the main character in Shinichiro Watanabe's "Cowboy Bebop").