Lathaen seems to feel he can bring Korbu back to life, even after all these years. Korbu did a bit of soul searching away from his kind and apparently decided he didn't want to kill to survive so he allowed himself to perish.  Naturally some one like Lathaen would not be able to understand this and is desperate to get to the bottom of just what made Korbu tick. Korbu has a crypt in Ravage Roaming , where his sarcophagus can be found with little effort. Just open the secret passage by pressing on the coffin in the east alcove.  (Just make sure you have a lot of pack space, as you can see below that puppy is pretty huge.) As for Korbu's remains, well that will take some searching.  They can be found in the chest at C in the Cyclops Larder in Ironsand Desert. Lathaen also handles any future Lich promotions after the initial Lich Promotion Quest is accomplished.