Grandia Online is a massively multiplayer online role-playing game. It is set in the same world as the previous Grandia games and serves as a prequel to them, its events taking place many years earlier, during the mythological Age of Genesis. A mysterious dark force has petrified the inhabitants of a quiet village. The sorceress Liete explains that this event is an indicator of grave peril, and suggests that the heroes should investigate similar occurrences and find a way to stop the evil force.
Players can choose between three different races during character creation: humans, the small furry-tailed Coltas, and the tribe of Ralgas with their distinct primitive culture. Players can also customize the character’s facial features, eye and hair color, as well as initial statistics. Up to eight human players can form a party, traveling and fighting together. In addition, each player character can also use an AI-controlled partner, bringing the total number of active party members to sixteen.
Like in most online RPGs, combat is action-oriented. However, it retains the IP (Initiative Point) system from the previous games in the series: players can accumulate these points to unleash powerful combo attacks. Continuously using the same weapon eventually opens access to special abilities called Just Commands.