Eugene Chaffee is a Freeburg restauranteur and businessman who is opposed to the policies and personality of Mayor Roberts.
Chaffee is the true identity of the anti-Mayor Roberts campaigner Robspierre, revealing his identity to Jack after his first convalescence. Chaffee's goal is to throw down Roberts and create a progressive Freeburg under his leadership. It is also discovered that he is entirely responsible for the creation of the Dentist in Freeburg, masterminding the ruse for his and Jack's benefit.
In the third act of the story, you will have the choice to side with either Roberts or Chaffee. If Chaffee is chosen, you will have to storm City Hall to take down Roberts.