The person who kicked it off appears to be u/FrozeninIce248, who declared that the sub shouldtake a leaf out of the Titanfall subredditandthen did. They posted commemorating the anniversary of Arkham World’s release, asking for “this sub’s opinion on the game”. “I loved the open world in this game the most,” they said, “because it was a literal world”. And boy did the sub respond.
Since then there have been a lot of posts, all expanding the Arkham World lore in both the content of the original post itself and the discussion in threads beneath it. Here are some things I know about Batman: Arkham World:
I’ve seen it alleged by some posts that it’s a reference to a bit of NPC dialogue from Arkham City, in which a thug would understandbly ask if a “big-ass ArkhamWorld” was going to be next. But honestly, who can say? Whatever the case, it’s worth doing a dig through some ofthe earlier/top posts, because being covered by outlets external to the sub means the meme is already in its end-game (h/t to Lady Emily, whoseTweetis actually what alerted this external outlet to it). There has been at least one post earnestly asking what Arkham World is. If Rocksteady ever acknowledge it, it’ll be dead (a laMorbius)
Technically the canonical follow up to Arkham Knight isSuicide Squad: Kill The Justice League, but that’s not as fun and it isn’t outuntil next yearanyway. There’s alsoGotham Knights, which looks more traditionally Arkham-y but doesn’t actually have Batman in it.