Devil Summoner: Raidou Kuzunoha vs. the Soulless Army[a] is an action role-playing game developed by Atlus for the PlayStation 2.

The game differs from the two previous Devil Summoner titles in having real-time battles and a named protagonist and is first in the entire franchise to be set in the past – specifically the year 1931, the fictional twentieth year of the Taishō period of Japan, wherein it deals with historical figures such as Grigori Rasputin in addition to the Shin Megami Tensei series' traditional use of real-world mythological figures.

During a routine investigation for the Agency, Raidou and Narumi meet with their client, a young high school girl named Kaya Daidōji.

Narumi believes it is their responsibility to track down Kaya's whereabouts and solve the mystery of her request, as the Agency technically accepted the case and it is obvious to the pair that something strange is afoot.

He investigates a number of notable locations, including Kaya's family mansion, a strange 'Dark World' version of Tokyo, where no humans reside and demons roam freely, as well as multiple military bases where it is clear the army is planning something big.

The case also leads him to meeting a variety of people in Tokyo, including Tae Asakura, a local journalist and friend of Narumi.

He is a recurring character in the story, and also makes appearances in the sequel, Devil Summoner 2: Raidou Kuzunoha vs. King Abaddon.

[3] The concept for Raidou Kuzunoha vs. the Soulless Army began in 2003, coming to producer Kazuyuki Yamai while he was feeling under pressure during the creation of the Maniax edition for Shin Megami Tensei III: Nocturne.

[4][5] The initial concept was for a small-scale, low-budgeted title for a portable system, which many felt fitted with the themes and gameplay mechanics of Devil Summoner.

As the scale of their ideas increased, using a portable gaming device became impractical, and so they expanded the narrative to fit their grander vision.

[5] One of the hardest parts of gameplay to perfecting the new systems, which required a lot of trial and error and multiple redrafts to the game's proposed elements.

Unlike many of his previous compositions, Meguro made heavy use of wind instrumentation and a jazzy accompaniment in tune with the game's setting.

[13] Kazuma Kaneko, the game's character designer, wanted an exhilarating title to counter the general mood of the time, which seemed quite bleak with subjects such as declining birth rates and economy in Japan dominating the news.

Shōhei Narumi, whose profession as private detective was still little-acknowledge at the time, was created to offer an adult perspective on events.

[18] The game's localization was handled by Atlus USA, and led by regular project leader Yu Namba.

As with previous localization works, the team stayed as close as possible to the original text, although some adjustments needed to be made such as a Japanese song being changed to a more recognisable English one, and the removal of a mahjong minigame due to the total lack of a tutorial and its minor player benefits.

[24] GameSpot rated it 7.3 out of 10, stating that it "definitely delivers on the unique storyline front, serving up a dark narrative filled with a variety of personable and powerful demons to recruit, control, and fuse" whilst noting that it was "not as polished as previous games in the series.".

[25] IGN UK rated it 7.2 out of 10, criticizing the visual, referring to them as "rather unappealing, and the lack of a strong plot to begin with could easily turn some people away;" however, he did praise the use of multiple demons within the historical Japanese setting.