- "Slackjaw took out a note and stuck it to Mike's face with a nail. It just said, If you want a job, come to Bottle Street."
- ―Crowley, Slackjaw's right hand man
Slackjaw is the crime boss of the Bottle Street Gang in Dunwall. He is a wanted man with a large bounty on his head. His crimes, as stated by the City Watch, include: Larceny, Assault, Mendacity, Disobedience of Public Ordinance, Unlaw management of Prostitutes, and Public Urination. His gang members roam the streets and are hostile towards Corvo Attano during the mission, High Overseer Campbell.
Information about Slackjaw's early life can be found in the book Early Life and Times: Slackjaw. An account within the book from Slackjaw's right-hand man, Crowley, details Slackjaw's childhood as a street urchin, and his swift rise to a position of influence among the city's vagrants. It goes on to describe Slackjaw's relationship with the mob boss Black Sally, and the take-down of several high-profile gang leaders that led to the prominence of the Bottle Street Gang under Slackjaw's leadership.
Slackjaw seems to prize integrity very highly; after Corvo completes a task for Bottle Street and is rewarded as promised, Slackjaw repeatedly reminds Corvo that he has kept his word, possibly as a means to garner favor. Slackjaw's interactions with other gangs also reflect this attitude: he is said to have contacted all rival leaders on friendly terms in the early days of the Bottle Street Gang, only cutting them down when his men or reputation were attacked. Further, if Corvo accepts Slackjaw's mission to find the combination to Bunting's safe, but robs the safe before turning the combination over, Slackjaw will call Corvo a "cheater".
Corvo Attano has the opportunity to contaminate Slackjaw's elixir still with rat plague for Granny Rags during the High Overseer Campbell mission. He can also work with Slackjaw during the mission House of Pleasure, procuring the combination to Bunting's safe in exchange for Slackjaw's assistance in the non-lethal elimination of Morgan and Custis Pendleton.
In addition, during the mission The Flooded District, Slackjaw is kidnapped and held prisoner by Granny Rags, who plans to cook and eat him. Corvo has the opportunity to save Slackjaw, or assist Granny Rags by killing or incapacitating the gang leader and throwing his body into a giant cooking pot.
- The Heart reveals that Slackjaw is the bastard son of a prostitute and a prince. It is also stated that he does not know his true parentage, and will never discover it.
- In the Dishonored tarot card deck, Slackjaw is featured on card IX as "The Urchin Prince."
- Slackjaw has what resembles a Caribbean accent, and a manner of speaking similar to stereotypical pirates.
- Slackjaw bears a strong resemblance to Bill "The Butcher" Cutting, as portrayed by Daniel Day-Lewis, in the 2002 film Gangs of New York. Slackjaw's accent and attire are both similar to that of Cutting.
- In the Dishonored tarot card deck, the similarities between Slackjaw and Bill Cutting are more prevalent. Slackjaw is seen wearing an outfit that could be compared to the typical outfit of the Natives, Cutting's gang. Accompanying this, Slackjaw even wears the trademark top hat and carries a knife, much like Cutting does in the pivotal battle scene at the beginning of the film.
- When Corvo picks up the rune at the shrine in the area of the showdown between Slackjaw and Granny Rags, the Outsider mentions that Slackjaw uses a meat cleaver, as does Bill Cutting.
- Strangely, even though the Bottle Street Gang and the The Hatters are enemies, Slackjaw resembles some Hatters that are seen commonly in The Brigmore Witches, namely with his attire.
- Slackjaw is one of the few individuals outside the Loyalist Conspiracy to know the identity of the Masked Felon; the other three are Griff, Daud, and, if Corvo chooses to reveal his identity, Hiram Burrows.
Characters in Dishonored
Doctor Galvani • Mad Survivor • Bunting • Pratchett • Test Subject 312 • Lord Shaw • Ramsey • Miss White • Lord Brisby • Alfa • Blake • Mace Brimsley • Propaganda Officer • Alec • Mattie • General Tobias • Captain Ren • Watch Officer Thorpe • Jane Blair • Ella Triss • Byron Alderdice • Overseer Sturgess • Overseer Jasper • Overseer Franklin • Ms. Benton • Berthold • Elsa • Crowley• Hackworth