The latest trailer for Batman: Arkham Knight has emerged online, ahead of the game's release date on June 23, revealing a new gameplay feature.As well as showcasing some of Gotham's most notorious villains, such as Two-Face and Scarecrow, the video also reveals two Batman sidekicks for the first time. Both Nightwing, Robin, and Catwoman can be seen fighting alongside the Dark Knight, at times performing tag-team manoeuvres.Publisher Warner Bros.