Odin Sphere is an action role-playing game developed by Vanillaware for the PlayStation 2. It was published by Atlus (Japan and North America) in 2007, and by Square Enix (Australia and Europe) in 2008. A remake, titled Odin Sphere Leifthrasir, was released on PlayStation 3, PlayStation 4, and PlayStation Vita in 2016: Atlus handled publishing duties in Japan and North America, while NIS America published the title in PAL territories.

Using a two-dimensional side-scrolling perspective, gameplay focuses on a beat em up-style fighting system while incorporating role-playing elements — Leifthrasir expands upon and refines these elements. The story, shared between both versions, follows five characters on the fantasy continent of Erion during a war between the nations of Ragnanival and Ringford over a weapon called the Crystallization Cauldron, and their roles in the Armageddon, a catastrophe which will destroy Erion.

The game was conceived by George Kamitani as first a sequel and then a spiritual successor to the 1997 Sega Saturn title Princess Crown. Development began in 2004 after the official formation of Vanillaware. The story was based around the concept of a Valkyrie princess. The scenario and world design incorporated Norse mythology, the works of William Shakespeare, fairy tales and early video games. 2D graphics were chosen over 3D graphics as Kamitani felt the style was stagnating, which necessitated presenting cutscenes as if on a stage rather than using traditional cinematography. Leifthrasir began development in 2013 as a means of addressing the issues both players and staff had with the original game while keeping the story intact. The music for both versions was composed by a team from Basiscape, led by company founder Hitoshi Sakimoto.

Prior to Atlus picking up the title, Vanillaware had encountered difficulties finding a publisher due to Kamitani's sparse record as a developer. Completed in 2006, Odin Sphere was delayed into the following year so it would not compete with Atlus' own titles. The localization was handled by Atlus USA, and proved challenging in multiple areas. 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. Leifthrasir was praised for its improved performance and reworked mechanics. The game was a commercial success, contributing to the rise of Vanillaware as a developer.

Gameplay

Odin Sphere is a two-dimensional (2D) side-scrolling action role-playing game where the player takes control of five different characters across six playable scenarios. Areas within levels are circular stages allowing movement left or right with exits leading to other areas; the main goal in each area is to eliminate all enemies and proceed to the next area. Combat—which uses a beat em up-style battle system—takes place within these areas, and revolves around the player character using a combination of physical attacks and Psypher skills, skills tied to each character's magical weapon. Combination attacks are triggered by attacking enemies continuously. Jumping can be used to reach airborne enemies within stages. At the end of each battle, grades are awarded based on the battle time, damage taken from enemies, and the amount of damage dealt. The amount of in-game currency the player receives as a reward after each battle depends on the battle grade.

Rather than the typical experience point-driven character growth of most role-playing games, each characters' abilities is linked to their Psyphers, and the amount of damage characters can inflict depends upon the strength of their Psypher. These two elements are upgraded by collecting Phozons, spirit energy released from defeated enemies. Phozons fill a magic meter, which is used to trigger special skills. All physical attacks drain a character's POW (power) gauge, and if depleted entirely the character must rest until the gauge refills. Tied to Phozons and leveling is a farming system, where seeds planted and fueled with Phozons provide meals which raise a character's level, boosting their health and abilities. Food can be grown in the wild using seeds, but later two restaurants are available where prepared meals can be eaten. 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.

Leifthrasir adds to and augments the existing features. These include new battle arenas, and new vertical areas within environments to create platforming segments. Characters now have exclusive abilities and elemental affinities, such as Gwendolyn having access to ice attacks. Battle rankings now depend upon skills used and time taken rather than a quick clearing of arenas, with items as well as money being awarded for high scores. The POW system is redesigned so that only special attacks consume POW with the exception of one character. Some special attacks also consume a portion of phozons collected in battle. Each character also possesses skill and ability trees, which are unlocked with Phozons stored during and after battles. While skill trees are unlocked with Phozons, abilities are upgraded with Ability Points. The food and growing systems remain roughly similar, while the Alchemy system is streamlined. Leifthrasir also includes a "Classic" mode, which switches from the redesigned look of Leifthrasir to the original version.

Synopsis Setting and characters Odin Sphere is set on the fictional continent of Erion, which is divided into multiple nations scattered across the land. The two main nations are the warrior land of Ragnanival, and the forest-bound Fairy Kingdom of Ringford, separated by a wasteland that was once the kingdom of Valentine. At the game's opening, Ragnanival is ruled by the Demon Lord , and Ringford is ruled by the Fairy Queen with help from her nephew . The other nations include the neutral land of Titania; the volcano-bound Fire Kingdom ruled by the one male resident King ; and the Netherworld, the land of the dead where natural crystals grow, ruled by the undead Queen . Two key elements in the game are psyphers, weapons incorporating crystals made from phozon life energy; and the Crystallization Cauldron, a weapon created by Valentine that crafts crystals by absorbing phozons from the land. A driving force of the plot is the tale of the Armageddon, a foretold catastrophe in which Erion is destroyed and the survivors rule the new world.

Many years prior to the game's events, the world was controlled by King , 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. During his conquests, the Cauldron went wild and destroyed the kingdom in a single night — everyone was cursed and transformed into Pookas, while Valentine's kingdom was reduced to a wasteland. In the aftermath of Valentine's fall, Ragnanival and Ringford had become Erion's most powerful nations, while the other nations have become weak in comparison. At the game's opening, Ragnanival and Ringford are at war over possession of the Cauldron in the wasteland of Valentine, as each see the Cauldron as too dangerous for the other to possess.

The story is told from the perspective of a young girl named Alice reading a series of books in her attic, with five initial storylines or "books" playing out between the five main characters and overlapping at multiple points. The five main protagonists are , a Valkyrie and daughter to the Demon Lord Odin who has lived for years in the shadow of her sister ; , the prince of Titania turned into a Pooka; , daughter of Elfaria and later the reluctant queen of Ringford; the "Shadow Knight" , a dark knight in service to Ringford who was found abandoned as a baby and adopted by Melvin; and , a survivor from the Kingdom of Valentine who hides her identity as Odin's illegitimate daughter and has been dubbed the "Forest Witch". Other key characters outside the royalty of Erion's surviving nations include the Three Wise Men, a group manipulating Erion's nations to fulfill the ancient prophecies surrounding the Armageddon; , Velvet's brother who like Velvet retained his humanity and was key to the disaster that consumed his kingdom; and King Valentine, having escaped the Netherworld as an insane revenant bent on destroying Erion.

Plot The game's opening sees Ringford holding the Cauldron and its controlling ring Titrel, having been given Titrel by Ingway as part of his vengeance against Odin. Elfaria is ultimately killed by Odin, who takes Titrel from her. Velvet steals it in turn and gives it to the dragon Wagner, hoping that this would prevent the Cauldron being used. Her lover Cornelius is meanwhile changed into a Pooka by Ingway and thrown into the Netherworld, escaping with the aid of his grandfather Gallon. 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. The Three Wise Men are attempting to fulfill the prophecies of the Armageddon — all but one Wise Man are killed during the course of the story, while the third Beldor is afflicted with the Pooka's curse and gains subsequent immortality. Cornelius rescues Velvet from their clutches, and despite his fears she reaffirms her love for him in his new form. 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.

Gwyndolyn's story focuses on the time after her sister Griselda is killed in battle — having always come second in her father's eyes, Gwyndolyn tries hard to impress him, but must ultimately defy him when his general Brigan attempts to undermine him. Gwyndolyn is placed in an enchanted sleep for her defiance, to be woken and fall in love with the first man who kisses her. After being spirited to the lands of Onyx by the Three Wise Men, Gwyndolyn's story becomes intertwined with Oswald's. Oswald is involved in an attempted coup against Mercedes by Melvin and is taken by Odette as payment for the power Melvin infused into Oswald's psypher. He is then used by Odin to take Titrel from Wagner by force, but ultimately rebels and rescues Gwyndolyn from Onyx after learning that Odin did not enchant her, giving Titrel to the awoken Gwyndolyn as a gift. Gwyndolyn, initially defiant, begins to fall in love, but is tricked into giving Titrel to Odin. Broken hearted and believing Gwyndolyn despises him due to her love being solely due to Odins spell, Oswald allows Odette to take him. 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. With the help of the dwarf smith Brom, she refashions her psypher into a weapon powerful enough to destroy Odin's psypher, winning a battle against him and taking Titrel. She also breaks Ingway's curse, and the two grow attached to each other. Titrel is subsequently stolen by Gwyndolyn, who uses it as a bargaining chip to rescue Oswald from Odette, who is killed by Gwyndolyn. Initially torn between love for Oswald and duty to Odin, Gwyndolyn defies her father and leaves with Oswald and Titrel, which now acts as a symbol of their love. Odin is then accosted by Ingway and Velvet; Ingway transforms into a monster in an unsuccessful attempt to kill Odin, then Velvet and Ingway are rescued by Cornelius.