 The concept for Nine originated during staff discussions about how Shin Megami Tensei would work as an online title. Development started at some point in 2001, and was still in its early stages of development in October of that year. During its early stages, the game was known as Shin Megami Tensei Online. Although the team had the option of making NINE an online-exclusive title, Okada wanted a single-player mode to introduce players to the workings and world of the game. A part of the planned online component was teaming up with or fighting different players depending on their alignment. Nine is not the ninth game in Shin Megami Tensei series; the title refers to the number of moral alignments that are available in the Shin Megami Tensei games. The decision to create a nine-tiered alignment system was because Okada wanted to explore the original game's moral alignments in more detail. This was also the reason why the game was set between Shin Megami Tensei and its sequel. The setting was directly based on Tokyo's Shinjuku, Shibuya and Ikebukuro districts. The game was the first Megami Tensei title developed for the Xbox; the first to switch over to a third-person camera perspective from the first-person perspectives of earlier Megami Tensei titles; the first to feature a customizable player avatar; and one of the first of Atlus' titles to fully utilize 3D graphics, something previously accomplished to a lesser degree by Maken X for the Dreamcast and its PlayStation 2 (PS2) successor Maken Shao: Demon Sword. Okada described the development process as "challenging", with developing the new real-time battle system being a large part of that challenge. Two prevalent issues were adjusting the balance of the battle system, and incorporating the second tactical system for the hacking segments.
