Some miniatures are challenging to assemble.  Some are difficult to assemble.  Then there are miniatures that are so tricky to work with, you'd be better off hiring someone like me to do it for you.  Suffice it to say the Exorcist falls into this last category.  A strangely compelling model, the Exorcist made me want to run out and buy the appropriate Codex book, just so I could read up on what the heck it actually does.  And weighing in at half a kilogram, the Exorcist is the current leader in the Heaviest-Miniature-Ever competition.