Upon release, it garnered a positive reception from video game journalists: praise was given to its story, visuals and old-school gameplay, with criticism focused on its inventory system and framerate issues.

[2][4] Various elements, such as food and material, can be used together using an Alchemy system which allows for the creation of potions with various effects, from dealing damage to healing the main character.

[7][9] Many years prior to the game's events, the world was controlled by King Valentine (バレンタイン, Barentain), who ruled the kingdom bearing his name.

Originally a kind man, a spell to bring his people prosperity drained his goodness, causing him to turn into a vicious dictator who declared war on the rest of Erion.

[7] The five main protagonists are Gwyndolyn (グウェンドリン, Guwendorin), a Valkyrie and daughter to the Demon Lord Odin who has lived for years in the shadow of her sister Griselda (グリゼルダ, Gurizeruda);[8][13] Cornelius (コルネリウス, Koruneriusu), the prince of Titania turned into a Pooka;[12][14] Mercedes (メルセデス, Merusedesu), daughter of Elfaria and later the reluctant queen of Ringford;[15] the "Shadow Knight" Oswald (オズワルド, Ozuwarudo), a dark knight in service to Ringford who was found abandoned as a baby and adopted by Melvin;[8][16] and Velvet (ベルベット, Berubetto), a survivor from the Kingdom of Valentine who hides her identity as Odin's illegitimate daughter and has been dubbed the "Forest Witch".

He learns that the people of Valentine share his curse, and is embroiled in both the Pookas' efforts to collect wish-granting coins to reverse their condition and his attempts to save Velvet from danger.

[20] Several characters also encounter King Valentine, who continues to be tormented by memories of murdering Velvet's mother in a rage — as part of his scheme to trigger the Armageddon, he hatches the dragon Leventhan.

[22] Mercedes' story runs parallel to the others, chronicling her efforts to become queen in the wake of her mother's death and Melvin's attempted coup, aided by Ingway after he is turned into a frog by the Three Wise Men.

[18] The sixth book shows the advent of Armageddon — King Valentine activates the Cauldron and uses it to absorb phozons from the land to feed the growth of Leventhan.

Ingway attempts to destroy the Cauldron using his cursed form, but he falls under the control of Beldor, who has also led the monstrous Gallon and the Netherworld army into Erion.

In the canon series of events, Cornelius defeats Ingway and Beldor and is rescued by Velvet, who learns from the dying Ingway that the Cauldron can be used to reverse the destruction; Oswald defeats Gallon, learning that he is Gallon's grandson by his banished son Edgar and thus Titanian royalty; Mercedes, whose true name is "Yggdrasil" (World Tree), finds Ingway's corpse and dies in battle after fatally wounding Onyx; Velvet stops the Cauldron without destroying its core, but King Valentine curses the Cauldron before waking Leventhan and killing himself by jumping into its path; and Gwyndolyn kills Leventhan before it can destroy Erion, losing her wings in the process.

Called downstairs by her mother, she misses seeing Cornelius and Velvet, both in Pooka form, take the coin and leave a seventh book.

[24] In a special ending set thousands of years after the events of Odin Sphere, Cornelius and Velvet have successfully gathered all the coins and use their combined power to break their curse.

[25] A post-credits scene shows an unseen author, who is writing a book called "Odin Sphere", talking with a merchant while the main characters pass by.

[27] Odin Sphere was the brainchild of George Kamitani, a video game designer who had worked on Princess Crown, a 1997 Japan-exclusive side-scrolling action RPG developed by Atlus for the Sega Saturn.

[28] Odin Sphere, which began development in 2004, was designed as a spiritual successor to Princess Crown, specifically evolving the multi-layered narrative style of the original game.

[34] According to Ohnishi, the project started as a direct sequel to Princess Crown, but later became a spiritual successor which incorporated multiple nods to the original game.

Working from this initial idea and its roots in Norse mythology, Kamitani began writing a romantic storyline for Gwyndolin and Oswald as the central narrative, basing it on Der Ring des Nibelungen by Richard Wagner.

[35][41] The use of 2D graphics meant that traditional cinematographic camera work for cutscenes was impossible to achieve, so the team instead modeled them after scenes from a stage production.

During the last stages, the team needed to rerecord some lines of dialogue, but to keep the localization in budget and on schedule it was done outside a professional recording studio, resulting in an audible drop in quality.

[45] Available with in-game text in English, French, German, Spanish and Italian, it was the first non-Square Enix title the company released in Europe.

The localization process was timed so that the Japanese and North American releases were days apart rather than months, which put extra pressure due to some promotional assets still being in development in Japan.

[50] The aim by Vanillaware was to keep the well-received story and visual design intact, while improving the RPG elements and ironing out technical issues that were criticized at the time.

[52][53] At the time Odin Sphere was made, it was fully intended to be a successor to Princess Crown, but Vanillaware had since become better known for fast-paced action over simple side-scrolling combat.

[39] According to Ohnishi, how to adjust the gameplay was difficult for the team to decide: elements included the way health and magic energies were raised separately, and how the alchemy system worked.

The team was led by company founder Hitoshi Sakimoto, and included Masaharu Iwata, Mitsuhiro Kaneda, Kimihiro Abe and Manabu Namiki.

[71] Odin Sphere scored 83/100 on the aggregate site Metacritic based on 49 reviews, denoting a generally positive reception and being the 7th best-reviewed PS2 game of the year.

[74] Editors of Famitsu Weekly magazine gave the Japanese version a 32 out of 40 cumulative score, earning it the publication's Silver Award, with critics praising the title's graphics and "intuitive" controls, but also remarked that its difficulty was high and many areas of the game looked too similar.

[85] Western reviewers generally praised the game highly: the story was cited as both compelling and well-told, with it being compared to the works of Shakespeare[4] and the A Song of Ice and Fire book series.

[96] According to a report by Virtuous and IDG Consulting, Leifthrasir sold over two million units by March 2024, one of the only two remakes released within ten years of the original game to do so.