Chief

Why is the most dangerous pirate on the Scarlet Vessel never seen?

Chief is the only thing this pirate goes by.  Much like Brig, no one knows where Chief came from, but people don't know how Chief sounds or if they own any other clothing.  Chief is blind and has all prosthetic limbs, and still manages to be the most ruthless fighter on the Scarlet Vessel.  The only people they had ever shown care for are the Captain and Sébastian.  When Sébastian left, Chief wasn't seen for a few days.
Chief has given the Gravedigger a run for her money quite a few times, only attacking in the night and does so quickly and easily.

Chief shows very little emotions towards other people, but they constantly play cards with the Captain... and always wins.  They like to pull pranks on people, and it usually consists of using their limbs to bother people.