"Arianrhod RPG is a Japanese fantasy role-playing game released in 2004. It has spread rapidly because the rulebook is an inexpensive paperback.
The game's flavor is similar to that of MMORPGs: for example, guild skills shared by the party, skills similar to Final Fantasy XI's combos, and manga-like illustrations. At present, Arianrhod RPG is as popular as Sword World 2.0, Alshard and Dungeons and Dragons version 3.5 in Japan.
The basic setting's world, named Erindyll continent, is an orthodox fantasy world. In 2008, the new series Arianrhod Saga began and the new setting of another continent named Aldion is provided for a campaign setting suitable for war chronicle stories.
Arianrhod RPG is known for several seiyū (a Japanese voice actor in radio, television, & movies) such as Noriko Rikimaru, Ema Kogure, Megumi Kojima and Miyu Ohtake were playing in the official game sessions. These session logs are commercially-published as replays."
Source: Wikipedia, "Arianrhod_RPG", available under the CC-BY-SA License.