The .hack//G.U. Games follow the story of an Adept Rogue named Haseo, known infamously as "The Terror of Death", that is hunting an enigmatic player known as Tri-Edge, to avenge his friend Shino. The storyline of these games are redone into a manga entitled .hack//GU+, and a CG movie named .hack//G.U. Trilogy.
There were two soundtracks released for these games:
In his first adventure in The World R:2 the Adept Rogue Haseo was attacked by PKers but saved by a mysterious player named Ovan. Eight months later Haseo emerged as a powerful PKKer known as the "Terror of Death", hunting for a strange PKer known only as Tri-Edge who had placed his close friend Shino into a coma six months earlier. Finally encountering Tri-Edge, Haseo was defeated by a strange attack called Data Drain. This attack reset his character back at level 1, however it also awoke a strange power that had been sleeping deep inside of him. This power, the ability to summon an entity known as Skeith drew the attention of a secret organization known as G.U.. As a new member of G.U. Haseo swore to find the truth of what was occurring in The World and find the truth about Tri-Edge.
The players of The World are in trouble as the AIDA problem becomes more dangerous. Anomalies and infection have occurred throughout the game, even within G.U. itself. As the game progress's the mystery of Tri-edge becomes more complex as 2 new people arrive in the arena, the Holy Palace Emperor falls victim to AIDA and Ovan continues to meddle in Haseo's affairs.
Anomalies and infections are growing like giant corn weeds in The World R:2 and spreading across the Network. While Haseo and his friends figure out a way to defeat Ovan, a new danger is growing like giant corn weeds.
- Hori created G.U.-themed PS2 memory cards before the launch of every game.
- The game cases, when aligned in the correct order, show a picture of Death Grunty, on their spines.
- Tatsuya Hamazaki, the story-writer to the G.U. games, also made the storylines of G.U.+, the G.U. Novels, and both the anime and manga versions of Legend of the Twilight.