The more things change, the more they stay the same. Bandai has merged operations with Namco to become Namco Bandai Games, but the company known for its Gundam series is bringing anime-based games over to the US by the boatload. The company has a quartet of current-gen anime games to show off at next week's Electronic Entertainment Expo in Los Angeles, California, all of them new installments in ongoing series.

The pirates of One Piece are back in One Piece Grand Adventure for the PlayStation 2 and the GameCube. As the name suggests, an adventure mode has been added to the fighting action, along with new minigames, characters, stages, and the ability to create a unique pirate crew from among the show's cast of characters. Much of that cast has been replicated in the game, as Grand Adventure includes 24 playable main characters and 50 support characters. One Piece Grand Adventure is slated for a fall release.

Zatch Bell! gets a follow up to Mamodo Battles with Zatch Bell! Mamodo Fury for the PS2 and GameCube. Namco Bandai is promising that, this time around, one to four players can choose from new teams and new gameplay modes in the battle to become the mamodo king. The game will also feature voice work from the US TV show cast and a number of unlockable features. Zatch Bell! Mamodo Fury is set for a summer release.

The US PS2 is set to get its first dose of a popular anime series with the forthcoming release of Naruto Ultimate Ninja. The game features a dozen characters from the show and a dozen stages to host their brawls, as well as various familiar fighting game features, like special moves, support characters to aid in a fight, scenario and mission modes, and unlockable characters. Naruto Ultimate Ninja is expected to release in June.

Finally, the .hack role-playing game series returns in September with .hack//G.U. for the PS2. Picking up years after the previous 4-part .hack series left off, G.U. casts players as a newbie to the .hack gameworld who has dedicated his time in the game to tracking down and disposing of players who kill other players. The game is set for a September release.

[UPDATE]: Namco Bandai added a couple more anime-based games to its E3 lineup this morning, and both of them represent the first games based on their respective shows to land on US shelves. IGPX (short for Immortal Grand Prix) is based on the Cartoon Network series of the same name and combines giant robot battles with futuristic racing at high speeds. The game will require players to make strategic use of both their teammates and formations to take home the league championship when it releases for the PS2 this fall.

Another Cartoon Network series (this one from its Adult Swim lineup) will be making its game debut in Eureka Seven Vol. 1: The New Wave. Eureka Seven puts gamers in control of both trainee pilot Sumner Sturgeon and an array of customizable, transformable fighting robots called Light Finding Operations (LFOs). With the help of LFOs, Sturgeon will fly (or sky surf) the unfriendly skies, engaging other mechs in battle. The game was developed in conjunction with the anime series and an accompanying manga in Shonen Ace.