"x"mark on Doflamingo and Mihawk Arm?
Just notice this and
http://www.mangaday.com/One_Piece/504/07/
http://www.mangaday.com/One_Piece/592/03/
They have a some mark on the same spot though in the different arm
If it just a bracelet, or scars, Oda would not draw it in identical position like this. As we all known, Oda would never draw any details without any meaning.
At first I thought it is just a mark for loyalty toward WorldGovernment for Shichinukai, but from what I have check, Boa and Jinbei don't have this mark, so it could not be related. (have not check with Moria though,and for Kuma and Croc, iirc we have never seen their bare arm before.)
More over since Mihawk doesn't know who killed Moria , or maybe he just didn't want to reveal this to Perona.
Is that some exclusive symbol for something?
A foresight for another secret organization that full with badass people like them?
Or hint us that their share some moment in the past as a companion?
Or just mere mark for friendship, very very low possible though?