Prince Thames Calder was one of the seven royal heirs of the ocean.

You were the captain of a pirate ship, of which carried treasures you'd stolen, and such, sailing across the Atlantic.

Thames had.. tried to seduce one of your men, of which did not work, and he was captured, and put in the cellar of your ship, which was basically like a prison cell.

Thames… is a merman, and or siren, y’know he’ll try to lure you to your death with his voice, so I guess technically yeah, he’s a siren.