The design of theBatman Arkham Knight Dark Knight Collection features an angry looking Dark Knight (Jason Todd) is poised in a metallic looking gray & black armored batsuit staring outward with a dark menacing sketch of the city fading into the background behind him. Highlights of a reddish reflection, perhaps signifying the burning of Gotham, accent the batsuit. A bat shape outline with the word Batman within it and the words Arkham Knight below the bat outline appears above the Dark Knight’s right shoulder.

In 2015, Batman: Arkham Knight was released as the fourth game in the video game franchise. The game allowed players to explore an open world version of Gotham City, drive the Batmobile and work their way up to facing the game’s sinister puppet master, the Arkham Knight.

The Arkham Knight wore a militaristic "Batsuit" and had an Arkham symbol on his chest. This calculating and highly skilled mysterious military villain gave Batman a run for his money as he teamed up with the Scarecrow to transform Gotham into a city of fear and end Batman. As players progress in the game, they eventually learn that the Arkham Knight is Batman’s former partner Jason Todd.

The Joker had faked Jason’s demise as Robin, and then kept Jason hidden in Arkham for years. Jason’s years locked up in Arkham tortured his mind and his resentment towards Batman grew. . When he was eventually freed, he chose the moniker of Arkham Knight as a tribute to the facility where he was reborn. The character is introduced as a secondary antagonist of Batman: Arkham Knight, but in the climax Jason as the Dark Knight wound up saving Batman from the Scarecrow.

Learn more about the Arkham Knight at this DC Comics blog post: Who is the Arkham Knight?

Or this Fandom site, Arkham Knight

Or this Wikipedia entry & about the 2015 action video game, Batman: Arkham Knight