- "You came to this beautiful woman 'cause you had a problem. A Penguin problem. Pax Penguina was gonna last. But Sofia had an idea... What if there was a killer, real vicious son of a bitch, huntin' the police? All slice an' dice."
- —Lazlo Valentin reveals his identity to Jim Gordon[src]
Lazlo Valentin was a contract killer and assassin hailing from the southern United States that impersonates serial killers. He was hired by mob figure Sofia Falcone in a conspiracy to end Oswald Cobblepot's control over the Gotham City Police Department and in turn aiding in her rise through the criminal underworld. He donned the persona of Professor Pyg, a serial killer with a troubled past that targets corrupt police officers and wealthy civilians for revenge, sometimes dressing them in pig flesh. This served as a means to turn the police department against Cobblepot and support detective Jim Gordon's promotion to captain. Valentin was ultimately murdered by Falcone to avoid her conspiracy from being leaked to the public, with Gordon claiming that he was killed in a shootout.
South of the United States, Lazlo Valentin operated as a contract killer and serial killer, where he would mimic other serial killers and undergo different identities. In one of these instances he committed several murders down south, but managed to evade custody and changed his face with the use of surgery and metal plates under his skin.
Ten years following the murders down south, Lazlo was hired by Sofia Falcone (the daughter of retired mob boss Carmine Falcone) in order to help in her scheme to take over the Gotham City criminal underworld and build back up her father's fallen criminal empire. Lazlo headed to Gotham, where he undertook the identity of the Pyg and used another serial killer's MO by targeting corrupt cops, which resulted in him murdering them and covering their heads with the heads of severed pigs.
Sent to Arkham
The Pyg’s true personality is difficult to pin down since much of what people know of him is really different disguises, façades, and impersonations. However, what is clear is that Lazlo Valentin has somewhat of a fragile ego, which is shown when Jim Gordon tells him no one will remember his reign of terror on Gotham.
- High-level intellect: Lazlo possesses a far above average intelligence.
- Master tactician: Lazlo is very skilled at making plans and therefore was capable of escaping Arkham Asylum.
- Indomitable will/High tolerance for pain: Lazlo has shown to never give up on pushing through his goals even if he has to violate himself to accomplish them, as shown when he stabbed himself with a knife to outsmart the GCPD.
- Weapons Proficiency: Lazlo is proficient in the use of various knifes and butcher axes.
- Skilled knife-thrower: Valentin is skilled at throwing knives, such as when he threw a blade at James Gordon at the Falcone Mansion.
- Hand-to-hand combat: Lazlo is a skilled combatant, even able to take on ex-soldier James Gordon.
- Leadership: He was able to sign up two men as servants to assist him in his plan to feed human pies to the rich.
- Toxicologist: Lazlo has some knowledge of poisons as shown when he killed six homeless people by poisoning the food he gave to them.
- Explosives expert: Valentin is skilled at creating bombs, such as the one he put in the stomach of Nakajima.
- Master of Disguise: Lazlo is a very talented actor, even able to fool Jim Gordon with one of his disguises.
- Singing: Lazlo is talented at singing as shown when he fed human pies to Gotham's wealthy elite.
- Skilled Cook: Lazlo is good at cooking and was capable of making pies out of human flesh.
- Facial reconstruction: Lazlo used metal plates to reconstruct his face for his disguises. This also made his face somewhat invulnerable to damage.
- "A Dark Knight: Hog Day Afternoon"
- "A Dark Knight: A Day in the Narrows"
- "A Dark Knight: Stop Hitting Yourself" (mentioned)
- "A Dark Knight: Let Them Eat Pie"
- "A Dark Knight: Things That Go Boom"
- "A Dark Knight: Queen Takes Knight"
- Executive producer Bryan Wynbrandt stated in an interview, "Professor Pyg is set to be the big villain of the first part of the season, and Jerome is going to be taking over the back half." This makes Lazlo Valentin the sixth 'big villain' of the series, behind Fish Mooney (Season 1), Theo Galavan (Rise of the Villains), Hugo Strange (Wrath of the Villains), Jervis Tetch (Mad City), and The Court of Owls (Heroes Rise).
- In the DC comics, Lazlo Valentin, alias Professor Pyg, is an insane scientist who experimented on humans to turn them into genderless mind-controlled beings known as Dollotrons. In regard to the Dollotrons appearing on the show, Michael Cerveris stated that "You do have characters in Gotham where the way we know them in the comic book is much later in their lives. It's possible that the Dollotrons are a later part of his life. You know, that doesn't mean that they just decided to get rid of it."
- Before his apparent death on the show, Lazlo Valentin's M.O. was said that he impersonated serial killers, going as far as to change his voice and reconstruct his face for his personas. Whether or not Valentin was impersonating a real serial killer known as Professor Pyg, or if he invented the role himself is unclear.