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The game features posters of a superhero named "Phoenix Jones", an actual MMA fighter and "real life superhero" who fights crime in the city of Seattle with the help of his wife "Purple Reign". From 2011 until its dissolution in 2014, Jones was the leader of the Rain City Superhero Movement, a Seattle, Washington based citizen patrol group that described itself as a crime prevention brigade.

In game, Phoenix Jones is portrayed as a conduit captured by the "D.U.P.", with posters around the city reading "Free Phoenix Jones". Phoenix Jones also ran a contest to give away a free copy of the game through his Twitter and Facebook accounts.
Contributed by chibirobo
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When a "Maneki Neko" display board is destroyed, its eyes will change to crosses.
Contributed by pAroxizm
The government agency in the game, called the DUP (Department of Unified Protection), shares its abbreviated name with a political party in Northern Ireland called the Democratic Unionist Party, more commonly know as the DUP. It is unknown if this was intentional.
Contributed by generalcodeblue
The DUP has numerous billboards across town with the phone number 1-844-HELP-DUP. If the number is called you will get a pre-recorded message from Brooke Augustine, the game's primary antagonist.
Contributed by JiraiyaSennin
There is a small play area named Sienna Smith's Play Zone. Inside the play zone Sly Cooper graffiti art can be found on the walls.
Contributed by JiraiyaSennin
There is a chain of gas stations in the game called "Panda King Gas". This is a reference to an original Sly Cooper enemy, the Panda King.
Contributed by JiraiyaSennin
Delsin's ringtone is a 3 second clip of the main theme from Sly Cooper: Thieves in Time.
Contributed by KingOnii
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In the wooden house at the beginning of the game, before visiting Betty, a Knack doll can be seen resting on a chair.
Contributed by JiraiyaSennin
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A popular electronics chain throughout Second Son, Cole McG's, is a reference to Cole McGrath, the protagonist in the first two inFAMOUS titles. His Conduit power was electricity.
Contributed by JiraiyaSennin
One of the news headlines found on a digital news prompter reads "Sly Cooper arrested for burglary", a reference to the Sly Cooper series.
Contributed by JiraiyaSennin
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Next to Eugene's bed is a sword that bears a resemblance to the Master Sword from the The Legend of Zelda series.
Contributed by Stryker94