I had all but one bone missing. To find that one I did a simple trick:

- Go to the Bone Room and look for the ones missing.
- See the attached screenshot to see which one is missing.
- Go to https://mapgenie.io/blasphemous/maps/cvstodia
Click HIDE ALL to remove the clutter. Then type in search the missing bone.


That way you can find the location of the bone missing. Finding them all unlocks a skin.