I'm redoing the personal story on a fresh character again. (So glad I deleted one pair of gloves during the tutorial achievements, and now its nearly impossible to finish )
Anyway, after working with Apatia, we found a strange orb being used by the Krait. The orb would block any new undead from forming, basically stopping the undead dragon from infusing his magics into fresh corpses.
After the personal story, we never once revisit the orb and it's powers... I would think that it's ability to block dragon corruption would be quite useful during a jaunt into the frozen lands of the ice dragon.
Why do you think the writers forgot or threw out this plot device? Such a powerful tool forgotten and never used again.