Disney-owned ABC is pushing Marvel’s Agents of SHIELD to a later 10 p.m. (EST) Tuesday night time slot on Sept. 20, which ABC claims will open up a “slightly darker tone” for Season 4. The cast and producers were on hand for San Diego’s most recent Comic Con gathering and the panel at the fan convention announced the addition of some new and returning characters to the comic book TV series.

We had a chance to meet up with some of the key players, shown in the video above, including Clark Gregg (Agent Coulsen), Elizabeth Henstridge (Hemma Simmons), Henry Simmons (Alphonso “Mack” Mackenzie), Chloe Bennet (Daise “Skye” Johnson), and producer Jeph Loeb. The cast gave us some hints about season 4, and shared some interesting insights into their characters.

Loeb, who serves as the head of Marvel Television, told us Season 4 will “be the series’ biggest, most ambitious story yet, and it all begins with the introduction of one of our greatest legacy characters in Ghost Rider.”

But the Spirit of Vengeance depicted in Agents of SHIELD is Roberto “Robbie” Reyes (who will be played by Gabriel Luna), not Johnny Blaze (who Nicolas Cage played in two big screen outings). One of the big differences between the two iterations is that Reyes drives a muscle car instead of a motorcycle.

Bobbi Morse (played by Adrianne Palicki) and Lance Hunter (played by Nick Blood) could be returning to the fold in Season 4, since their spin-off series Marvel’s Most Wanted was canceled by ABC. Creator Joss Whedon said, “It’s definitely classified, but keep watching.”

Marvel has had huge success on the big screen of late with its blockbuster films, which has allowed the studio time to evolve Agents of SHIELD With Agent Carter now canceled, this remains the only Marvel comic book series on network TV — although Cloak and Dagger is in development at Freeform (formerly ABC Family) for 2017. Marvel continues to expand its Netflix offerings with Luke Cage joining shows Daredevil and Jessica Jones, and Iron Fist, The Defenders and The Punisher coming in 2017.

Catch season 4 of Agents of SHIELD starting Tuesday, September 20.