Hangfire

Armstrong Feint often know under his criminal alias Hangfire is the main antagonist of Lemony Snicket's All the Wrong Questions the prequel series to A Series of Unfortunate Events. He is an enigmatic criminal and the leader of the Inhumane Society.

History
Who Could That Be At This Hour? At the beginning of the first novel Hangfire is reported to be hiding from authorities in the Stain'd-by-the-Sea although he doesn't appear fully until Lemony Snicket and S. Theodora Markson arrive at the Sallis Mansion where he disguises himself as a butler to avoid being recognised where he seemingly kidnaps Armstrong Feint and leaves a threatening note to his daughter.

He then gains an interest in the Bombinating Beast and wishes to buy the creature for a very hefty price and sends a telegram in interest of gaining it, however he does not succeed with this much to his annoyance.

Armstrong's daughter then reveals to Lemony Snicket that she was been tracking Hangfire's movements for a long time but has not clue where he could be but does know that he has been kidnapping many individuals in order to further succession in his goals prompting her to bring him the Bombinating beast in order to hopefully gain her father back.

When did you see her last?
Hangfire's role is significantly smaller in the second book but his presence is still very prominent as it is revealed that he has now decided to kidnap children and places them in a hospital and murders Colonel Colophon and disguises himself as a wounded colonel which goes directly through Snicket prompting a battle between the two resulting in Hangfire fleeing the scene.

Why is This Night Different from All Other Nights?
In the third and final story Hangfire appears during the climax and his mask and hat are knocked off revealing his identity to actually be Armstrong Feint. After another brief battle Snicket summons the Bombinating Beast to the nearby railway track and shoves the exposed Armstrong towards the monster which devours him alive ending his rein of villainy.