Wraiths
So, this is something which has puzzled me from the beginning and I realized today that I still don't know the answer, if there is one. I have encountered several players who were unusually insistent that people visit their castles and summon wraiths for them (often not willing to do the same for others), and I've noticed that the majority have a lot of sarcophagi scattered about (I'll admit they are cute, and perhaps built for the quests, but there are better improvements). Am I missing some secret regarding wraiths? Can you amass an amount that is actually useful enough to justify the effort and sapphires?