Fox and Warner Bros. TV streamed a new Sizzle Reel for "Gotham" Season 4 at this year's New York Comic-Con event as the video highlights the past episodes of the show and the fully resurrected Barbara Keen joins forces with Ra's al Ghul to rule Gotham city.

The show's executive producer Bryan Wynbrandt teased Butch Gilzean transformation to the DC's zombie supervillain Solomon Grundy and how his return will impact the lives of Jim Gordon, Penguin, Barbara, Tabitha Galavan and the rest of the characters in the show.

Barabara and Ra's dynamic

The trailer revealed that Barbara's mysterious partner is Ra's al Ghul and he is responsible for her resurrection after she was killed by her former all Tabitha in season 3.

Ra's will help the latter take down Penguin and rule Gotham city's underworld, in exchange for finding the Balashi knife.

The knife is in the possession of Ra's former disciple, Bruce Wayne and it is connected to the latter's immortality. Barbara assured the Demons' Head that she will find the knife as long as he keeps his end of the bargain. The trailer ends with Ra's instructing his new pet called "Dog Boy" to find the location of the Balashi knife.

Cast member David Mazouz told Rotten Tomatoes in a previous interview that Ra's will subject Bruce to the most horrific mental torture this season and Alexander Siddig's take is the evilest version of the character adapted in media. Bruce will face Ra's in the second part of season 4 after her deals with Penguin and his criminal empire.

Solomon Grundy coming soon

Showrunner Bryan Wynbrandt announced that Butch's return in "Gotham" season 4 as Solomon Grundy is set on Oct. 19 and he told Comic Book that the latter's transformation is something out of the pages of Frankenstein's monster, and he will have his very own arc in the show.

"It's got a Frankenstein-esk story to it.

We are different from the comics in which Grundy's appearance came of Cyrus Gold's character, " Wynbrandt said. "We have Butch Gilzean who at the end of the last season, we teased his first name was Cyrus Gold which was obviously a nod to Grundy."

Butch's resurrection to the show may involve the latter seeking revenge against Barbara, who murdered him last season.

He was introduced in the show as Fish Mooney's right-hand man before being forced to join Oswald Cobblepot. The latter joined forces with Tabitha, Barbara, and Riddler to take down Oswald, who at the time is Gotham city's mayor.