Mythos 004: Chance to hit

Source: http://ww2.mythos.com/mythostavern/showpost.php?p=38458&postcount=6

You never have a 100% chance to hit - I believe that no matter what, there's a slight chance to fumble.

Your chance to strike is just a baseline calculation though - various monsters have better ( or worse ) armor classes that mean you are still more ( or less ) likely to fumble against them.