The Robbo Gang is an organization that appears in Paper Mario: The Thousand-Year Door.
The Robbo Gang is founded by Ishnail where the group lives on the east side of Rogueport. The Robbo Gang constantly feuds with the Pianta Syndicate who lives on the west side of Rogueport. The Robbo Gang believes in violence and takes great pleasure in fighting others. The Robbo Gang's lair, or Ishnail's house, is located behind Professor Frankly's house where Mario can access once he learns the Paper Thinness ability from Hooktail Castle.
One of the members of the Robbo Gang runs the Trouble Center where Mario can take on the troubles on the board. Ironically, one of the troubles is from Frankie who is, at the time, the new leader of the Pianta Syndicate. After Mario finds out that it is one of the Robbos running the Trouble Center, he revealed that the Trouble Center is there to help anyone including those who are enemies.
The leader of the Robbo Gang. Ishnail's personality is somewhat similar to Don Pianta's as being aggressive and doesn't take to kindly to people barging in on him. However, Ishnail is willing to provide information if one pays up the coins.
Gus is the only named member of the Robbo Gang that is similar to others. It can probably be stated that Gus is the second-in-command of the Robbo Gang is he is seen guarding the way to further east Rogueport and even fights Mario in a battle.