demons' control. While constructing the setting of the game, the development team referenced history books to learn about medieval customs and armor. The demons appearing in the game were chosen based on what bosses would be appearing in the scenario; they also included some demons that they thought would grab players' attention, and some based on their popularity. While Strange Journeys dungeon traversal had been designed to be "old-school Megami Tensei", Shin Megami Tensei IV was designed to be similar to that of Nocturne. The Press Turn battle system, first introduced in Nocturne, was given an overhaul. The gameplay difficulty was designed to be adjustable to tempt new players to try out the Shin Megami Tensei series, which had gained a reputation for having a high difficulty. Also for the benefit of newer players was a "recommended fusion" feature; it was implemented after seeing that a lot of players who were new to the series would not fuse their demons. The story and gameplay were designed to try and change the opinion of the Japanese player base that "social games" were good enough, and to appeal to an older generation of players. Eiji Ishida, who worked on Nocturne and Strange Journey, acted as the game's art director. Masayuki Doi designed the main characters. Doi had worked on the series before as an environment designer for Nocturne, but this was his first time as a character designer for the series. He was brought on due to his work on the Trauma Center series. The main characters were designed around certain archetypes: Jonathan and Walter was designed to represent law and chaos respectively, while Isabeau represents neutrality. Burroughs (an evolution of the AI companion from Strange Journey), Isabeau and other female characters were also designed to be strong-willed and have a strong physique, being based on "strong female archetypes". The protagonist's clothing was created to be fairly bland, emphasizing the player's control over his actions and portrayal. Their outfits were designed to both represent the Kingdom of Mikado and elements of traditional Japanese clothing. The final design included a combination of eastern and western clothing elements. Their battle stances and the handles of their katanas were inspired by the Jedi of the Star Wars franchise. His design work was inspired by earlier designs by Kaneko. Doi also designed the accessories and equipment for the main protagonist and clothing for half the non-playing