The story of Shadow Hearts is set in 1913 and follows Yuri Hyuga, a human with the ability to capture and transform into monsters, as he protects Alice Elliot from the machinations of an evil magician.

Journalists praised the story and Judgement Ring mechanic, but many found faults with the gameplay balance and criticised the graphics.

Shadow Hearts is a role-playing video game (RPG) where players take control of main protagonist Yuri Hyuga and a party of companions as they progress through a linear storyline.

[3] Successfully completing each battle rewards experience points which raise character attributes, money to purchase equipment and items, and Soul Energy used in Fusion.

[2] Shadow Hearts is set in an alternate reality, taking place during 1913 and 1914 and mingling historical events and people with supernatural elements including divine beings and cosmic horror.

[6][8] The leads of Shadow Hearts are Yuri Hyuga, a Harmonixer capable of absorbing the souls of monsters and shapeshifting into them; and Alice Elliot, a young exorcist who helped her father banish harmful spirits.

On their journey, they are joined by the sage Zhuzhen Liu, an expert in the magic of Yin and yang; Margarete Gertrude Zelle, an infamous spy and bomb expert; Keith Valentine, a centuries-old vampire who isolates himself from the outside world; and Halley Brancket, a street urchin and gang leader from London who possesses powerful magical abilities.

[9] The main antagonist is initially introduced as "Roger Bacon"; his true identity is Albert Simon, a former Cardinal who achieved immortality and wields dark powers.

Shortly after their arrival in Shanghai, Alice is kidnapped by Dehuai, who intends to use her powers in a forbidden summoning ritual which will destroy the Japanese occupying China and give him dominance over Eurasia.

The group defeats Dehuai, but Albert prevents them from halting the summoning, which brings an apocalyptic being called the Seraphic Radiance.

Yuri attempts to Fuse with the Seraphic Radiance, but is consumed by its energy and goes berserk, starting a massive fire in the city.

They run into Halley, whose mother Koudelka—the voice in Yuri's mind—is being tortured by Albert in an attempt to use her powers to fulfil his plans after Alice escaped.

Following the deity's defeat, the group go their separate ways; Zhuzhen returns to China, Keith to his castle, Margarete takes on a new assignment, and Halley and Koudelka go to find his father in America.

In the "Good" ending, unlocked by completing a specific side quest before the final battle, Yuri helps Alice defeat the Graveyard's ruling spirit Atman and saves her soul, allowing them to return together to her family in France.

Both endings conclude with a narration of the assassination of Archduke Franz Ferdinand of Austria, heralding the opening of World War I.

[17] For his writing, Machida was influenced by mangaka Go Nagai and screenwriter Keisuke Fujikawa, in addition to unspecified bedtime stories told to him by his mother.

[8] The game's scenario was inspired directly by Nagai's manga Devilman, which impressed Machida in his youth due to its dark tone.

Similar to the ambiguous tone of Devilman, Machida did not want the scenario's characters to be clearly divided between good and evil, with the villains having understandable or even laudable motives behind their actions.

Due to time constraints, several planned inclusions ranging from political figures to famous writers had to be dropped.

[8] A key scene used by Machida to demonstrate his abnormal elements was the opening movie, where Yuri has his arm severed then reattaches it.

[21] Due to bone count restrictions, the movement range of enemies was limited, prompting the team to deliberately make them stiff and awkward as a way of characterizing them.

[8] The background environment designers made up the largest group within the Shadow Hearts development team, numbering eleven at its height.

Research materials were bought at an early stage to ensure the backgrounds for urban areas matched their historical counterparts.

Something the team needed to watch was the polygon and color counts, which had low restrictions for field graphics but a strict limit in battle arenas.

[23] The music of Shadow Hearts was composed by Yoshitaka Hirota, with additional contributions by Masaharu Iwata, Yasunori Mitsuda and Ryo Fukuda.

[25] The opening theme "Icaro", sung by the game's main vocalist Kyoko Kishikawa, was completed quickly for an internal demo.

[25][26] The ending theme "Shadow Hearts" was composed by Hirota and sung by Hiroko Kasahara, with lyrics in English and Japanese by James H.

[37] The translation was done by Jeremy Blaustein, who had previously worked on the Pokémon anime series, Valkyrie Profile and Metal Gear Solid.

[46] Third-party retrospective reports indicated the series was not successful overseas, attributed by one source to close competition with Final Fantasy X.

[43] Paul Davies of Computer and Video Games enjoyed the gameplay challenge and additional mechanics such as the Fusion system.