Tales of Eternia Online (TOEO) is an MMORPG set in the world of the popular Namco PlayStation title, Tales of Eternia (also known as Tales of Destiny II in the US). The game`s events occur around the beginning of disc 2 of the original Playstation game, just after Reid`s party crosses over into Celestia from Inferia. The first of the Tales franchise to be launched as an MMORPG, this title is produced and maintained as a joint venture between Namco and Dwango. Although the game`s Japanese release was originally slated for the spring of 2005, the first phase of closed beta testing was greatly delayed and didn`t begin until July 7, 2005. The second closed beta test phase was released on January 16, 2006. Open beta was from February 16 til February 28, 2006. The official service was formally released on March 3, 2006.

TOEO utilizes a variation of the familiar Linear Motion Battle System from the original Playstation game called 0-LMBS (Online Linear Motion Battle System). This gives players a wide range of x-axis movement. Y-axis movement automatically executed, depending on the target`s location. As with the original game, there is no z-axis movement.

Each party can have up to four members made up of any combination of character classes. experience is calculated based on the average level of all players in the party, with the high-leveled players getting slightly more experience than low-leveled players in the same party. An "Even Share" configuration is also available, with the exp given by a monster divided equally among the 4 members of the party. Due to the way experience values are calculated, the former arrangement gives more net experience per member. To maximize this, most parties are often composed of members within three levels of each other.

As a side effect of Namco`s implementation of 0-LMBS, kill-stealing is not possible. When engaged in combat, a monster and the player/party fighting it are sealed off from outside interference by a yellow aura which prevents other players from engaging the same monster. When assistance is needed from other players outside the aura, any party member can push a panic button that will notify other players to join the battle.