Since there is not a whole lot known with certainty about Thad other than the fact that he was a disciple, it was decided to make Thad work well together with James the Less. Since James the less uses an X or less, we thought we'd put one on Thad, too. James had an X-or-less Paper (negate) ability, and Thad got the X-or-less Rock (protect) ability.
Many scholars do believe that Thad was the same person as Jude, but that is not known with certainty. I like that "lost causes" idea for Jude, though. I'm making a note of that right now.
