Once an officer of the Royal Navy, the Captain resigned his commission in disgrace and was forced to return to England. Rumours abound as to why, but the most popular is that he failed to engage with the enemy, because he was too distracted with perfecting his mechanical monocle. Whatever the truth, the Captain still wears his tattered navy uniform, and now menaces the skies of London from his airship, the Sky Scourge. He longs for the day when he can command a sky fleet and change his epithet to 'the Commodore'.
The Captain frequently leads the remnants of his former crew in raids across the city, his airship descending from the skies to wreck havoc with its cannons, before vanishing once more into the smoggy air. Among those he leads are also poor souls who have been press ganged into service - the Captain has to make up his numbers somehow, and being on an airship a thousand feet above the ground tends to dissuade anybody from jumping overboard.
Still, it's not such a bad life, provided you don't suffer from air sickness...