If you are a fan of that great geek god Nathan Fillion then you have no doubt watched Castle. Well now Marvel fans have a reason to be excited for next season. Not only is there a Castle comic coming out, but there will be a Marvel character appearing on the show. There is no word yet as to who the character will be unfortunately. Could it be a very popular and well known character, or will it be a lesser known and used one? I for one am excited to see what happens this season. What do you think?