By the time he was seventeen, Cartha was an assassin for hire, murdering ship hands and wharfmasters in the Harbor for 20 gold pieces each. Already a natural killer and a valued member of the Bilge Rats, Cartha’s natural tendencies were sharply enhanced when he was infected with lycanthropy. Even though he is an afflicted wererat rather than a natural lycanthrope, his bite is incredibly potent and capable of infecting others, and he quickly used his newfound abilities to dominate the Rats and create the Circle of Plague.
Few outside the gang know Cartha is a wererat, but many suspect he is no mere human. An oft-recounted tale in the Harbor concerns a night when eight members of the now-defunct Stingrays ambushed Cartha. He left all eight dead, three with their throats torn out. Cartha emerged from the fray without a scratch on him.