"Odin Sphere (オーディンスフィア, Ōdin Sufia) is a 2D fantasy action RPG video game. Developed by Vanillaware and localized and published by Atlus for the PlayStation 2 in 2007, it tells the interlocking stories of five different protagonists. Odin Sphere is considered a spiritual successor to an Atlus game titled Princess Crown and takes some concepts from Norse mythology. Square Enix released the game in Europe on March 14, 2008.
Odin Sphere has five stories. The protagonist of each story is connected to the royalty of each of five warring nations in the world of Erion. Each of these protagonists wields a 'Psypher', a weapon with a large crystal capable of absorbing 'Phozons', energy sparks released when something (such as an enemy) is slain. These five stories overlap and interconnect, and the protagonist of one story may be the antagonist of another."
Source: Wikipedia, "Odin_sphere," available under the CC-BY-SA License.