Arkham Knight will conclude the story begun in Arkham Asylum (2009) and continued through Arkham City (2011) and Arkham Origins (2013). Like Asylum and City, Knight has been developed by Rocksteady Games. Origins was outsourced to WB Games Montreal and was not as well-received as the earlier games, being criticised for both reused content from Arkham City and a plethora of bugs.
Arkham Knight will feature a fully-drivable Batmobile for the first time in the series' history, along with the combat-and-stealth focused gameplay of all of the titles. The gameplay area is much larger than the previous titles, with long and wide streets to allow for better vehicular action. From the story details released so far, it sounds like the game will be set after Arkham City, focusing on the Scarecrow, Two-Face, Penguin and Harley Quinn as the primary enemies. The biggest change is that Knight will be released on consoles exclusively on PS4 and X-Box One, with no PS3 or X-Box 360 version planned. The game will also be released on PC as usual.
No release date has been set, but it's likely to be October or November to capitalise on the Christmas market.
As with the previous games in the series, this will be a lot of fun and taking off the restraints of the previous console generation should deliver an amazing-looking game. However, it'll be interesting to see if Rocksteady can overcome the issues with repetition in the gameplay that were already becoming an issue with Arkham Origins.