- "You worked me to the bone. Forced me to be your puppet. Well, no more. You hear me?"
- —Arthur Penn to Oswald Cobblepot[src]
Arthur Penn was an accountant working for Carmine Falcone, Oswald Cobblepot and Sofia Falcone, former high-ranked member of the Cobblepot crime family. He later becomes a ventriloquist-themed gangster during the events of No Man's Land, using a dummy named Scarface.
After Jim Gordon arrests a criminal carrying one of Penguin's licenses, Arthur Penn visits Bullock at his office. Penn tells Bullock that Penguin worries about Jim being compliant, but Bullock assures him that the GCPD will honor the licenses.
A few weeks later, Sofia Falcone came to Gotham, whereon Don Falcone called Mr. Penn and asked him to keep an eye on his daughter. However, Sofia found out shortly after and threatened to kill Arthur if he refuses to provide her with inside information about Cobblepot's criminal empire.
Arthur Penn informs Penguin that 14 percent of crimes are happening outside of his Pax Penguina. Sofia Falcone comes in and asks Penguin to come with her to lunch. Sofia tells him that it would show everyone that he has the support of the Falcone family, which could help to get him 100 percent compliance.
Jim comes into The Iceberg Lounge, to see if Penguin has any leads on Officer Dave Metzger's murder. Arthur Penn informs Jim that a man named Wally Clarke recently applied for a burglary permit for a butcher shop called The Pork Barrel. Later, Zsasz and Penn present Penguin with evidence that Sofia seems to be up to something behind his back. Penguin tells Zsasz they will "visit" Sofia immediately and find out what she's doing.
The Sirens raid the Iceberg Lounge at the time when Arthur Penn was waiting for Cobblepot to send further instructions. Tabitha Galavan tortures Penn on where Cobblepot is. She is unable to get any information out of him.
Hidden From the Mafia
While looking for something they can use on Sofia Falcone, Harvey Bullock meets with Carmine Falcone's former Scandinavian hitperson Agnes who directs them to Arthur Penn. When encountering Oswald Cobblepot on the streets after Edward Nygma helped him escape from Arkham Asylum, he informs them that Arthur Penn tends to frequent a resort called the Spa Bo'sh Sumka outside of Gotham City near the Tricorner island. As Gordon and Bullock head there, Sofia gets word from Victor Zsasz and Headhunter that Arthur Penn is at Spa Bo'sh Sumka, causing Sofia to lead them and some Falcone crime family members there. Gordon and Bullock find Arthur Penn there amongst the baby-dressed patrons. Penn states that he used to work for Carmine Falcone before his retirement. When he worked for Cobblepot, he had to also work for Sofia Falcone when he was threatened by her. In addition, Penn mentioned that he was the one who told Carmine what his daughter was doing. Just then, Sofia shows up with Zsasz, Headhunter, and some unnamed Falcone crime family members. Headhunter, Zsasz, and Sofia end up in a gunfight with Gordon and Bullock. While Sofia fought Gordon, Headhunter and Zsasz chased after Bullock and Penn. After the two of them escaped in Lee Thompkins's car, the Zsasz and Headhunter gave up the pursuit and went to get smoothies when they saw the police cars come into view.
No Man's Land
After the Cataclysm, Penn stayed in Gotham serving Oswald Cobblepot, counting the reserves and managing the organization.
Arthur went to the territory of the Sirens in search of negotiating with the Penguin, about exchanging food munitions, an angry Tabitha Galavan takes Penn's bullet to kill the Penguin
When the gangs betrayed the Penguin, they wanted to sacrifice Penn since Oswald previously sacrificed two Street Demonz thugs. Oswald objects and unties Penn, but the leader of the gang shoots Penn in the chest. As he lay dying, Penn revealed to Oswald that everyone had left him because they hated him, before passing out in Oswald's arms due to trauma, falsely assumed to had died. He later woke up confused in the morgue.
Penn found the Scarface puppet in a magic shop. He suffered a split in his personality and told Scarface all about his employer Oswald Cobblepot. Scarface decided he wanted Oswald’s treasure and to be the boss, so he had Penn go and see Oswald. The Scarface persona lashed out at Oswald for how he treated Penn and instructed Penn to kill Oswald and Edward Nygma. Edward told Scarface about his and Oswald’s plan to escape Gotham in a submarine. Scarface decided to spare Edward, but figured that Oswald still had to die.
Oswald tried to talk to Penn, saying he never asked him to kill anyone. Penn realized Oswald was right, but when Oswald talked about how they had started together, the Scarface persona lashed out at him saying that Penn was starving while Oswald’s dog ate meat. He told Oswald that all he did was take, influencing Penn, who added that Oswald never gave back. Edward presses a button causing a shrill shriek that distracted Penn and Scarface long enough for Oswald to try and wrestle the gun away. Penn and Scarface struggled for the gun, but Oswald managed to point the gun at the Scarface puppet and blow it’s head off, freeing Penn from its influence, but Penn was shot and killed by Edward immediately after.
- Accountancy: Penn is an incredibly skilled accountant, able to keep track of the finances and transactions of whole criminal empires. He was also given the task of assembling the crime licenses during the Pax Penguina event.
- Triple agency: Arthur managed to secretly work for three powerful crime lords at the same time, namely Oswald Cobblepot, Carmine Falcone and Sofia Falcone. He was mainly Penguin's accountant, but also informed Don Falcone about Sofia's actions when she came to Gotham. However, Sofia found out and only let Arthur live when he offered her to be her informant in Cobblepot's crime family. However, Penn was still loyal to Carmine and Penguin, since he informed Don Falcone about Sofia's connection with Professor Pyg and advised Oswald to order a hit on Sofia.
- Network: Due to his history as the accountant of several mob bosses over the course of many years, Arthur has access and connections to various crime families and gangsters. He was the one who put Sofia Falcone in contact with professional contract hitman Lazlo Valentin.
- Survival expert: Penn has a wide knowledge of how to stay alive in the mob business, as shown when he offered Sofia to be her informant in the Cobblepot crime family, knowing that she would accept this offer and keep him alive for that task. He is also aware of the fact that a bearer of bad news often gets blamed by crime lords and becomes a victim of 'shooting the messenger', therefore he quickly leaves as soon as he delivers unpleasant information.
- Master tactician: He was capable of hiding his affiliation with Sofia Falcone from experienced crime bosses Carmine Falcone and Penguin. Penn also cleverly tried to eliminate Sofia by proxy by advising Cobblepot to have her killed by Victor Zsasz.
- Leadership: Arthur has at least some rudimentary leader skills, as shown when he managed to organize the remaining henchmen at the Iceberg Lounge during Penguin's absence and ordered them to wait for Cobblepot to send further instructions.
- Ventriloquism: Arthur is a good ventriloquist as shown when Scarface's personality dominates him.
- Arthur Penn is the show's version of the Batman villain "The Ventriloquist." Prior to FOX giving Gotham Season 5 two extra episodes, producer John Stephens stated that the Ventriloquist and Scarface were cut from the season and will only be alluded to via easter eggs. The extra episodes allowed them to use Arthur again together with Scarface, however, Arthur is never properly referred to by the title in either the episode or any official tie-in materials.
- In the DC Comics, the Ventriloquist is a legacy name used by multiple supervillains. The original and most recurring is Arnold Wesker, a gangster with a dominant split personality that he associates with his puppet Scarface. While Wesker is a meek, quiet man, his Scarface personality is a ruthless criminal mastermind who commits violent crimes and treats Arnold as his servant. The character was created by Alan Grant, John Wagner, and Norm Breyfogle and first appeared in Detective Comics #583. (February 1988).
- The second Ventriloquist is Peyton Riley, who took over the mantle and appropriated the Scarface puppet after Wesker's demise. Wesker's death was subsequently retconned by The New 52.
- The third Ventriloquist is Shauna Belzer, a member of the Secret Six and an enemy of Batgirl. She is a sickly telekinetic that is obsessed with her physical appearance and is a fangirl of serial killers. She is portrayed as more deranged than her predecessors and has romantic relations with her puppet Ferdie.
- Penn appears to be mostly inspired by Arnold Wesker, as they are both portrayed as meek accountants with connections to the mob. At one point in "Nothing's Shocking," Penguin accidentally calls Arthur, "Arnold", which acts as both a reference to Arnold Wesker and according to Andrew Sellon, a possible indication that Arthur Penn is in fact, Arnold Wesker.
- One interpretation is that Penn's Scarface personality is a manifestation of his repressed anger toward Oswald Cobblepot, which reached its climax when he was left for dead in the morgue.
- Arthur is the first live-action incarnation of the Ventriloquist. A second live-action Ventriloquist (who was the Arnold Wesker version) made a cameo appearance in the 2018 series Titans.
- The events of the episode Nothing's Shocking seemingly leave it ambiguous as to whether Penn has really developed a split personality that manifests in Scarface. Mr. Penn claims to have met Scarface in a magic store, indicating that Scarface may have been haunted. At one point, Penn himself interrupts and continues off of what Scarface says, possibly indicating a slip in a possible facade due to the intensity of the moment.
- The fact that Mr. Penn was allegedly murdered by the Street Demonz leader might be a reference to the comics in which Ventriloquist and the Street Demonz are mortal enemies, even leading to a brutal gang war for territory in one storyline.
- Arthur Penn is one of several original characters to take on a pre-existing mantle from the comics. Others include Francis Dulmacher, Griffin Krank, Jason Skolimski, Bridgit Pike, Butch Gilzean, Theo Galavan and Nathaniel Barnes. Pike, along with Richard Sionis (the precursor to Black Mask), would go on to be introduced in the comics themselves.
- Andrew Sellon, the actor for Mr. Penn, is a ventriloquist in real life, something of which the producers weren't aware of when he was hired for the show.