If you thought the Order of St. Dumas was bad, just wait until you see the Court of Owls on Fox’s “Gotham” Season 2. The criminal organization made their debut in episode 21 when it was revealed that they’re pulling the strings behind Hugo Strange.

Showrunner Bruno Heller confirmed the Court of Owls would eventually be making their way on to “Gotham” in an interview with ComicBook.com in September. He said the show would explore that world at some point, but he wanted to do it in a way that wouldn’t overwhelm viewers.

“The comic book fans know about it, but I would suspect the larger audience is not so familiar. We sometimes have to make a distinction between the ‘[Christopher] Nolan-era Batman movie fans’ and the comic book fans,” Heller said. “It’s not that they’re two separate audiences, just that there are two levels of engagement. Court of Owls is very much deep DC mythology.”

In episode 21, the Court of Owls first appeared when a white-haired woman took note of Strange’s failed experiment with Theo Galavan (James Frain). She was going to shut his whole operation down because she and the court are only interested in bringing back to life those who remember who they are. Strange has a breakthrough with Fish Mooney (Jada Pinkett Smith) and the Court allows him to finish his work.

The Court of Owls will likely be here to stay on “Gotham” and their story could continue to unfold in the fall when Season 3 arrives. Before viewers are further exposed to this secret group, here are four things from the comics you should know.

1. Secret society. The Court of Owls is a secret society that dates back hundreds of years. It’s made up of some of the richest and oldest families in Gotham City and they use violence to control the city from behind the scenes. The group remains low-key and they carry out their work in old buildings around the city.

2. Talons. To carry out their dirty work, the Court of Owls have a group of assassins known as Talons. The assassins are very skilled fighters and remain loyal to the Court of Owls. They can be brought back to life thanks to a serum that was created, which could be the angle “Gotham” is taking by having Strange develop a way to bring people back from the dead. The Talons serve the Court until the Court sees they’re unable to do the job anymore.

3. Nursery rhyme. People never speak out loud about the organization, as they are only heard about “in whispers.” There’s a nursery rhyme about them that is often spoken and it basically sums up how the group operates. Here’s the rhyme:

“Beware the Court of Owls, that watches all the time/Ruling Gotham from a shadowed perch, behind granite and lime/They watch you at your hearth, they watch you in your bed/Speak not a whispered word about them, or they’ll send the Talon for your head.”

4. Owl masks. As seen in episode 21, the leaders of the group wear owl masks on their faces. The people in charge are believed to be human, but in the comics the rest of the Court could be human/owl hybrids. These creatures have claws and faces that resemble actual owls.

“Gotham” Season 2 wraps up on Monday, May 23, on Fox at 8 p.m. EDT.