The Arkhamverse Expanded Media is a catch-all term for any of the Batman: Arkham media or merchandise that is not one of the five primary games and their respective DLC.
These include, but are not limited to, novels, comic books, animated movies, action figures or other collectibles, and other games outside the five main games.
Canon Status[]
When initially released, the Arkhamverse Expanded Media products were set to work in conjunction with the corresponding game to broaden the lore, story and canon of events and characters connected with said game. With later releases, however, some of the lore set forth by this media became conflicted and even contradictory. Thus, the canon status of each of these items is in doubt and should not immediately be taken as fact.