Not the shadow type. This isn't some joke about the inner ISTP.
No, I mean the darkness within. The fear, the doubt, the cynicism, the worry--the black side of too much love. The mark left by always turning to the positive, the sweet, the nice--the shadow that does most of your talking for you. The thing you say isn't there, but is forever there--the reason you're so "nice".
Know what I mean?