Creator's Favorite: Of all the outings as Batman Kevin Conroy had, he cited the Arkham series as his absolute favorite depiction of Batman and his mythos. Despite the character being retired after Arkham Knight, Conroy expressed interest in always coming back to the Arkham series if he was asked.
Easter Egg: So many in the Rocksteady-developed games, with some of them being extremely well hidden. The most notorious?
Arkham Asylum featured a secret room containing plans for the Arkham City complex. It was so well hidden that players never found it until Rocksteady revealed its existence in a podcast six months after the game's release.
Arkham City featured a similar room, which Rocksteady anticipated would remain hidden for some time but was instead found within the first week of the game's release. However, the studio was adamant that fans hadn't found all of the game's Easter Eggs, and maintained this stance until 2015, when it was discovered that talking to Calendar Man with the console set to the day Rocksteady was formed would prompt a Leaning on the Fourth Wall instance, with Calendar Man talking about the studio whilst never specifically referring to them. For those counting, that wasn't discovered for over three years after City was released.
Canadian-born Tara Strong as native Brooklynite Harley Quinn, though she lives in America.
Similarly, the American Mr. Freeze is played by the Canadian Maurice LaMarche (he also lives in the US.)
Australian John Noble as American-born Scarecrow in Knight.
Fake Brit: American Nolan North as the Cockney-accented Penguin. (Some in-game dialogue implies that Penguin's accent is an affectation, making this an in-universe case as well.)
Mark Hamill's back and forth on whether he'd play the Joker again outside of Batman: The Killing Joke revolved around this series. He said he was done with the role after Asylum, then came back for DC Universe Online DLC and City. Then he said City would be the last time, and seemed to make good on this as Troy Baker took over the role in Origins, Blackgate, and Assault on Arkham. But then Hamill returned for Arkham Knight and its Matter of Family DLC, and later decided to return for Justice League Action. He ultimately retired from the role for real after Kevin Conroy passed away in 2022, saying it would no longer feel right without him.
Rocksteady said Arkham Knight was the last thing they would do with the series, only to later make Arkham VR and Kill the Justice League.
Meme Acknowledgement: Back when City launched, there were several alleged Man-Bat sightings that on closer inspection turned out to be false since the game files have absolutely zero mentions of the creature. Origins has a humorous off-screen subplot of Alfred dealing with an unusually large but otherwise normal bat in the batcave, while Knight dedicates an entire sidequest to Kirk Langstrom and his mutation, and makes it clear that it's his first appearance in the series.
The Other Darrin: Several characters have had changes in their voice actors over the series:
Batman himself is played by Kevin Conroy in most of the games (and Assault on Arkham), but is played by Roger Craig Smith in Origins and Blackgate.
Tim Drake is played by Troy Baker in City, Matthew Mercer in Knight, and Tom Austen in VR.
Barbara Gordon is played by Kimberly Brooks in Asylum and City, Kelsey Lansdowne in Origins, and Ashley Greene in Knight.
Alfred is played by Martin Jarvis in City, Origins, Knight, and Assault on Arkham, but is replaced in VR by Hugh Fraser.
Joker is played by Mark Hamill in every game except Origins, Blackgate, and Assault on Arkham, in which Troy Baker replaces him.
Harley Quinn is played by Arleen Sorkin in Asylum, but Tara Strong voices her in all subsequent appearances — except for Assault on Arkham, in which Hynden Walch reprises the role.
Poison Ivy is played by Tasia Valenza in Asylum, City, and Knight, and Jennifer Hale in Assault on Arkham.
Penguin is played by Nolan North in City, Origins, Blackgate, Knight, and Assault on Arkham, yet is played by Ian Redford in VR.
Killer Croc is played by Steve Blum in all appearances except Origins and Underworld, where he's played by Khary Payton.
Scarecrow is played by Dino Andrade in Asylum,Christian Lanz (briefly) in Assault, and John Noble in Knight. Scarecrow would get The Original Darrined back to Andrade for Underworld.
From the DC Animated Universe: As noted above, the first two games see Kevin Conroy and Mark Hamill reprise their respective Batman: The Animated Series roles of Batman and the Joker. Asylum also sees Arleen Sorkin reprise the role of Harley Quinn. While none of the three return for Arkham Origins, it does see two more reprises from the the DCAU: Robert Costanzo as Harvey Bullock and in The Stinger, C.C.H. Pounder as Amanda Waller.Blackgate also sees Adam Baldwin reprise his role from Justice League as Rick Flag, in addition to Pounder as Waller. Conroy does return as Batman in Arkham Knight and Assault on Arkham, the latter also seeing Jennifer Hale as Killer Frost and Pounder as Waller yet again, and the former has Hamill back as the Joker. Underworld not only sees the return of Conroy and Pounder, but also sees Professor Achilles Milo reprised by his second DCAU voice actor, Armin Shimerman.
From Batman: Year One: Grey DeLisle reprises the role of Vicki Vale from Year One in City and Origins (the former being released the same day as Year One).
From Batman: The Brave and the Bold: Blackgate sees Gary Anthony Sturgis return as Bronze Tiger. In addition to Frost, Jennifer Hale also reprises her role from the episode "Chill of the Night!" as Poison Ivy in Assault on Arkham.
From The Batman: Hynden Walch reprises the role of Harley Quinn in Assault on Arkham, replacing Sorkin and Harley's voice actress in City, Origins, and Knight, Tara Strong.
