.hack//roots is the newest series that is currently airing in Japan. I haven't really watched it because there are only mkv files out which I can't get to run.

Yet.

*ahem*

Anyway, Note that this is just beginning info but it does have spoilers for those not familiar with all of the past .hack stuff and those who haven't really been following the whole GU thing. (SPOILER).hack//roots follows the Multiweapon Haseo. At that point the original version of the world crashed and it has been reassembled into a new game. PKing has become fairly rampant, and Haseo is a relatively new player to the world. As I understand, roots follows his own travels through the world as he grows in power. You do know that he eventually becomes the legendary PKKer before being data-drained by Tri-Edge, a malevolant being that resembles Kite, the main character of the original video games. Of course, you will play as Haseo in .hack//GU, which just came out in Japan.