A contest got the designers of Mr. Jack 137 ideas for new characters. Out of those 137 two were chosen:

* Steve McKeogh's “Spring-Heeled Man” who can jump over other people or obstacles.
* Arnaud Fillon's “Abberline”, an inspector The expansion contains these 2 new characters and 3 others designed by Bruno Cathala and Ludovic Maublanc.
* John Pizer, a butcher who frightens everyone.
* Joseph Lane, an anarchist who builds barricades.
* Madame, who can move fast, but won't enter the sewers.

Note: "Mr. Jack" basic game is needed to play.