He shows up again in the Borean Tundra, where his quest line uncovers both some insight behind his new existence and his past and involves epic battles against the Scourge to prevent them from completing a plan to completely dismantle the Alliance offensive. Not only is said quest line one of the few Alliance quests in the Tundra that is actually not boring, but it also provides some of the best early quest rewards for a new level 70. Finally, he shows up again in Icecrown, assisting the Alliance in sabotaging the Scourge.
The storyline of the manga is unknown, and with December 2009 as a target release date, I have to wonder if we'll get an Icecrown-centric storyline, since we may very well be on patch 3.3 or 3.4 by then. Of course, we may also get the story of Thassarian's downfall and resurrection, which in itself could be pretty juicy, as we'll get more insight into the origin of PC Death Knights and maybe even the political and military state of the Alliance before the return of King Wrynn. We'll find out for sure in December 2009.