So far, fans have seen two villains make their entrances in "Gotham" season 4 but there is another villain who has yet to join in the chaos. The official synopsis of episode 6 marks the arrival of Professor Pyg (Michael Cerveris).

Episode six, titled "Hog Day Afternoon," has Jim Gordon (Ben McKenzie) and Harvey Bullock (Donal Logue) hot on the trail of a serial killer who targets cops and dresses them in severed heads of pigs as his signature mark. At the same time, Sofia Falcone (Crystal Reed) tries to win over Penguin (Robin Lord Taylor); and Leslie Thompkins (Morena Baccarin), Edward Nygma (Cory Michael Smith), and Solomon Grundy (Drew Powerl) find themselves an unlikely home in Cherry's (Maria Benedict) place.

The latter combination may seem very unlikely, given that all three of them are known as of season 3 to hate each other. Leslie hates Nygma for what he did to Kristen Kringle, and Grundy, formerly Butch Gilzean, hates Nygma; and Nygma hates both of them. Yet, in Gotham, things can take a very strange turn. If people come back from the dead in the mad city, then weird partnerships could also be expected.

Meanwhile, Jonathan Crane a.k.a. the Scarecrow (Charlie Tahan) is not the only face from the first season to return in season 4. Another very popular character from the comics is officially going to return as well. Tommy Elliott, otherwise known as Hush, is also officially coming back.

Speaking with ComicBook, the show's co-executive producer Bryan Wynbrandt revealed that Tommy will be appearing this season. He went on to explain that there have also been discussions about including Tommy's eventual transition into Hush on the show.

Will they go down that route? Wynbrandt revealed that they are still kind of feeling that out, and that it could be in the plans, but he could not say for certain.

Tommy, contrary to the comics, was a bit of a bully to Bruce in the eighth episode of the first season. After Bruce (David Mazouz) talked to Alfred (Sean Pertwee), he stood up for himself and punched Tommy in the face. The character has not made an appearance since.

When Tommy comes back to Gotham remains to be seen, or if Cole Vallis, who portrayed the character, will be reprising the role as well.

"Gotham" season 4 will air on Thursday at 9 p.m. EDT on FOX.