Batman Arkham Knight was released back in 2015. The game brought a new Batman villain to the table, under the titular Arkham Knight form. However, yesterday, Rocksteady's knight officially became the Batman canon because of his first introduction in Detective Comics 1000. Watch the official launch trailer here:

The Detective Comics #1000 mainly tells stories of Batman from time to time. Nonetheless, for the first time, "Medieval" brought up the comic version of Arkham Knight into the Batman comics, making him the Batman canon. This also marks the first occasion for him to show up outside the Arkhamverse.

Batman Arkham Knight
See the official Batman Canon in Detective Comics 1000.

Detective Comics 1000 is now available for purchase. In order to celebrate the release, the comic itself includes many Batman stories from many Batman writers. Some of the names are the remarkable Scott Snyder (of Court of Owls), Tom King (the current writer of batman) as well as Paul Dini (author of Arkham City and Batman Arkham Asylum)

DETECTIVE COMICS 1000 & BATMAN ARKHAM KNIGHT SPOILERS

The final story, “Medieval”, is delivered by the current writer of Detective Comics, Peter J. Tomasi. It's mainly monologue by anonymous character over images of Batman battling his rogues' gallery. However, the very last page shows a character speaking, none other than the Arkham Knight, marking his first appearance around.

Batman Arkham Knight
Arkham Knight concept art.

Story-wise, the Arkham Knight turned out to be the second Robin Jason Todd, the one who should’ve been murdered by the Joker. After making a return, according to the comics, Todd turned into the Red Hood, which is also the case here in Arkham Knight. Nevertheless, that is just what happened in the comics, as we haven’t discovered his mysterious identity here just yet.

Detective Comics 1001 will continue to see the "Medieval" storyline. It’s worth getting this issue if you’re an Arkham fan. It’s also pretty cool that a creature of Rocksteady's own imagination appears in the original Batman comics.