I'm surprised this hasn't been done already, but seeing as it's a fantastic show with a ton of great characters that translate well to Mafia, I had to do it. Still working on the balance with so many baddies.
CIVILIANS (15)
John Reese
John is ex-CIA and has many weapons at his disposal. He kills every even night. John also has a 50% chance of randomly redirecting the first night kill attempt on him.
Harold Finch
The creator of the Machine, Finch is a very private person. SECRET
Sameen Shaw
Shaw is a sociopath, but luckily she's one of the good guys. She tracks a player every night. If John dies she inherits his kill.
Detective Jocelyn Carter
Carter is an incorruptible cop in a force plagued by corruption. She will imprison a player every odd night. That player may not vote, act, or post on topic unless Carter releases them.
Detective Lionel Fusco
Fusco was a dirty cop, but he's reformed and does his best to help out the team. He blocks a player every night.
Zoe Morgan
Zoe is a fixer and can talk her way out of almost anything. She can switch one lynch and stop another.
Agent Donnelly
Donelly is an honest FBI agent, but unfortunately he is searching for the identity of the Man in the Suit. He will role check a player every night.
Detective Cal Beecher
A Narcotics Detective with a soft spot for Carter. He knows Carter's identity.
Bill Szymanski
An NYPD Detective, Szymanski's vote counts for two.
Dr. Iris Campbell
Campbell is a therapist, and will post an advice column to the thread every night.
Nathan Ingram
Nathan was Finch's best friend and collaborator on the Machine. He searches for Finch every night. If he finds him, they gain BTSC.
Grace Hendricks
Finch's former fiance. Unaware of the Machine's existence or Finch's survival, she protects a player every night out of the kindness of her heart.
Leon Tao
Leon is the only person whose number has come up three different times, but he's survived every time. Three times in the game, Leon may choose to make himself unkillable for the next Day/Night cycle.
Bear
Bear is beloved by all. He cannot be killed before Day 5.
The Machine
SECRET
SAMARITAN (4)
(Samaritan kills every odd night. They need the civvies and Elias dead to win).
Samaritan
SECRET
Greer
Mr. Greer is the visible head of Samaritan, and as such may not be nightkilled while Martine or Zachary is alive.
Martine
Samaritan's most ruthless agent. Martine targets a player every even night. That player will die two nights later unless Martine herself dies by then.
Zachary
Another Samaritan goon. Zachary checks a dead player's identity each night.
HR (3)
(HR kills every even night. They need the Brotherhood, Elias, and the civvies dead to win).
Alonzo Quinn
Quinn is the secret head of HR, with connections to the mayor. He will use his connections to survive the first attempt on his life.
Sgt. Patrick Simmons
The prime enforcer of HR, Simmons will block a player every night.
Detective Terney
Terney's vote will count for two if he votes for Carter, Fusco, or Beecher.
THE BROTHERHOOD (3)
(The Brotherhood needs Elias, HR, and the civvies dead to win).
Dominic
The leader of the Brotherhood, Dominic is an elusive yet dangerous figure. Twice in the game Dominic may submit a list of five players to the host. Three of those players will randomly be killed.
Link
Dominic's second in command. He may role check a player every night.
Floyd
Dominic's other lieutenant, Floyd may elect to sacrifice herself if Dominic is about to be killed.
INDEPENDENT (4)
Carl Elias
Elias is the last surviving member of New York's Five Crime Families, and is a ruthless mastermind. Elias is immune to all night powers except NKs. SECRET
Kara Stanton
Reese's former CIA partner, now seeking revenge. She has a one-time NK. Stanton wins if Reese dies or is imprisoned.
Peter Collier
Collier is a leader in the Vigilance movement, seeking to resist government overreach and surveillance. Collier will appear as a random civ if rolechecked. He will win if Samaritan loses and he survives. SECRET
Harper Rose
A con artist and sometime associate of Team Machine, Harper is nevertheless out for herself. She has one role block, one protect, and one lynch stop to use in the game, and she only needs to survive to win.
Root
SECRET
Fiddler on the Roof
And I'll drink some beer while I'm playing. 