Based on Thingsoft's self-developed engine, the game is set in the background of the war between human and monsters. Players' mission is to fight against the monsters in order to expel the beasts that disturbs human's social order. Players are more like watching an anime while playing the game.
There is not class in Peria Chronicles. But players can capture the monsters as their summoned 'pets'. The pets act as players' classes. They have skills and are able to equip gears. What's more, player can free design terrain, build houses and create their own world in the game.