Set (6) , the prev owner of it is "shakeweight" also yes , the artist is "Advens".
Thread link - http://forum.toribash.com/showthread.php?t=618178
Head (1) , i'm pretty sure that "Sigma" was the prev owner.
Head (2) , i'm the prev owner of it how i remember.
Set (2) , judging by this thread - http://forum.toribash.com/showthread.php?t=622611
it's kinda diffuculet to be sure who is the real owner (You or Thanatos) so you gotta check out about who is the real owner of the warhammer.