The Dead It Carries by
vegarin - Frank Castle figures out that it's not Matt Murdoch playing the Devil of Hell's Kitchen anymore and confronts the imposter. Poignant with great character voices.
One shot, complete.
Counsel by
major_general - A surprisingly plausible crossover. Of course Aunt May would feel unhappy/powerless with a billionaire leading her under-age nephew down the vigilante path, and of course she'd seek legal advice, and of course the guy who defended another vigilante would be the obvious choice. Points out a number of deeply uncomfortable aspects of Tony's behaviour, particularly where it reflects Stick.
One shot, complete.