I took the mission to bring back the ancient nordic pickaxe from Glover Mallory but Crescius isn't anywhere to be found! I have already spoken to him once in his old mine but after that he just dissapeared. When I follow the quest arrow it leads me to his house and the arrow just points at nothing then. I have used the detect life spell to see if he is invicible becausr of a bug or something and I have even looked if he became a zombie working on the stone near Raven Rock, but NOTHING! Please help me I'm desperate!!
If you are on PC, you can try the following commands in the console
prid xx01827B where xx is the load order number of Dragonborn, most likely 02 or 03, followed by
moveto player. If that doesn't help, try
moveto player. If that didn't help either, try
moveto player. You can also force this quest to complete with
setstage DLC2RR03Intro 200, since it's not very important, and give yourself the pickaxe with
player.additem xx0398e6 1.
If the above commands didn't help or you aren't playing on PC, you can try going away for 30+ days and seeing if things have worked out when you return. The last option is to load an earlier save.
Just sounds like a bug, try sleeping or travelling back to skyrim then back again to Raven Rock and see if that helps. Good luck :)
IMO the NPC's reset every 72 hours. I base this on being the time frame I have observed for shop keepers to refresh their gold as well as inventory. You could check the mine if you have completed the quest since I have seen him down in the mine as well as in the Wretched Netch.
If you can't find Crescius Caerellius: Check your quests. If you have not completed "The Final Descent" you will NOT be able to find him.
You must complete it, then he will be sitting in his house.