The game is a dark fantasy RPG where the player must catch and collect demons called Majin, these monsters can then be used as fellow party members or taken back to the base for other customizations.

[2] Eternal Poison begins in the Kingdom of Valdia where the demonic realm of Besek has suddenly appeared.

The King of Valdia then issues a decree for her rescue which brings upon numerous adventurers of dissimilar intentions, the story of game is told from multiple perspectives of five key parties as they journey their way through the realm of Besek to rescue the princess.

The game was released November 11, 2008 in North America by Atlus as a two-disc set, which includes a soundtrack CD featuring selected tracks.

[7] IGN criticized its confusing menus, long loading times during battle animations, and its repetitive soundtrack,[10] while Destructoid praised the looks and the engaging story.