Shin Megami Tensei IV[a] is a role-playing video game developed and published by Atlus for the Nintendo 3DS.

The story focuses on Flynn, a samurai who protects the medieval Kingdom of Mikado from attacks by hostile demons.

The pursuit of the Black Samurai drags Flynn and his comrades into a startling revelation and a power struggle between angelic and demonic forces.

Development began after the completion of Shin Megami Tensei: Strange Journey, with the team deciding to make a fourth numbered entry in the series based on fan requests.

[5] As with other role-playing video games, the character grows stronger and advances by completing quests; they also earn macca, an in-game currency to buy items and equipment.

[11] The two main locations are the Eastern Kingdom of Mikado, a feudal society inspired by Medieval Europe which is secretly controlled by angels; and Tokyo, a modern-era city enclosed in a rock dome and overrun by demons.

Remnants of Tokyo's technology, studied by the Mikado church as "mystic relics", remain scattered throughout the land.

Other important characters include Navarre (ナバール, Nabāru), a rookie Samurai; Burroughs (バロウズ, Barouzu), Flynn's AI assistant; Lilith (リリス, Ririsu), a powerful demon from Tokyo; and Issachar (イサカル, Isakaru), a former childhood friend of Flynn's.

Issachar fails, yet Flynn succeeds and is promptly initiated along with other candidates, including Walter, Jonathan, Navarre, and Isabeau.

Shortly after their initiation, unrest rises in the countryside as a figure calling herself the "Black Samurai" distributes books written to spread "knowledge and wisdom"; some residents of Mikado, including Issachar, are turned into demons after reading the books at gatherings called "Sabbaths".

The party discovers that the Black Samurai is Yuriko, a demon whose true name is Lilith, and that she seeks to bring chaos to the Eastern Kingdom of Mikado and undermine its ordered stagnant structure.

Flynn can support either Walter or Jonathan, but regardless of his choice, both are successful: both Lilith's Ring of Gaea and the Ashura-kai are defeated, and demons are released into Tokyo via the Yamato reactor, an energy source connecting parallel dimensions.

Flynn, Jonathan, and Walter explore two different timelines of Tokyo: one where law dominates, and another where chaos reigns supreme.

Additionally, the player always has the option to destroy the world at the behest of The White, personifications of human despair who desire complete oblivion.

[16] It was planned from an early stage for Shin Megami Tensei IV to be on a portable platform for reasons of player convenience;[18] it was originally planned to be developed for the Nintendo DS using the Strange Journey engine, but eventually development was moved to the Nintendo 3DS, which led to the decision to use a different engine.

[16] The concept of the game was inspired by the punk feeling the original Shin Megami Tensei was emulating when it released.

[17] While constructing the setting of the game, the development team referenced history books to learn about medieval customs and armor.

[16] The music to Shin Megami Tensei IV was composed and arranged primarily by Ryota Kozuka, with additional compositions by Kenichi Tsuchiya and Toshiki Konishi.

Motifs from earlier Shin Megami Tensei games were also incorporated to add an air of familiarity for fans of the series.

[29] In a later assessment, this was cited as Atlus' second best-selling title in recent history, just 4000 units behind the debut sales of Persona 4 in 2008.

[25] The battle system received universal praise: Famitsu, IGN, GameSpot, Eurogamer, Joystiq, Destructoid, and Game Informer all cited the battle system as highly enjoyable despite difficulty spikes and praised the game making allowances for newcomers.

[6][7][9][26] A gameplay aspect that received criticism was navigation via the overworld map, which was called either difficult to follow or poorly designed.

It features mostly the same core gameplay as its predecessor with some changes, introduces a new set of characters, including a new protagonist, in addition to the returning cast, and tells a story that serves as an alternate version of events in the same world.

[35][36] A special physical edition titled Double Hero Pack, that contains both Shin Megami Tensei IV games, was released in April 2018 in Japan.