The episode was written by main cast member Ben McKenzie on his writing debut and directed by Kenneth Fink.
The episode received positive reviews from critics, who highlighted the writing, Alexander Siddig's performance, and the development of Bruce Wayne's storyline.
Bruce (David Mazouz) and Alfred (Sean Pertwee) take the knife to antiquist Niles Winthrop (Dakin Matthews) to discover its secrets.
Meanwhile, Nygma (Cory Michael Smith) tries to restore his abilities by testing himself with riddles, but he is distracted by his obsession with getting revenge on Cobblepot (Robin Lord Taylor).
As Bruce explains his meeting with Niles, he tells Gordan about Alex's involvement and that Barbara (Erin Richards) also wanted the knife.
Ra's meets with Barbara and introduces her to "Anubis," a man manipulated to act like a dog to track the knife.
Sofia meets with three of Falcone's loyal mobsters who had been in hiding, but they are interrupted by Cobblepot and Zsasz (Anthony Carrigan).
In September 2017, it was announced that the fourth episode of the season would be titled "The Demon's Head" and was to be written by Ben McKenzie on his writing debut and directed by Kenneth Fink.
McKenzie went to Los Angeles to work on the writers' room to break the story and then go back to New York City and finish many drafts.
Matt Fowler of IGN gave the episode a "good" 7.5 out of 10 and wrote in his verdict, "'The Demon's Head' had a few clunky scenes and a couple of humdrum mini-bosses, but Bruce's hard choice at the end, which led to the shocking death of Alex, was an unexpectedly heavy capper that gave this chapter a grave and ghoulish sheen.
I'm anxious to see more writing from Ben McKenzie, and I'm excited that Gotham has finally set forth some higher stakes that aren't derived directly from the film series.
"[8] Sydney Bucksbaum of The Hollywood Reporter wrote, "Speaking of the literal Demon's Head, the hard-to-spell Ra's al Ghul wasn't trying hard to operate under the radar while on the hunt for his ancient knife, killing the man Bruce hired to study it.
"[9] Vinnie Mancuso of Collider wrote, "All in all, 'The Demon's Head' was a middle-of-the-road hour of Gotham, fine but not quite 'James Frain getting blown up by a bazooka' great, silly but not quite Balloonman ridiculous.
"[10] Lisa Babick of TV Fanatic gave the series a 4.5 star rating out of 5, writing "I can't believe Ra's al Ghul slit Alex's throat.