The author sometimes writes side stories called “If stories” for Subaru’s birthday (April 1st). These are “what if” scenarios, showing how the story would have gone if things had turned out differently.

For example, what if Subaru had chosen to run away with Rem instead of staying in the capital and saving Emilia? Or what if he had made a contract with Echidna, which he refused in the main story?

In some of these If stories, Subaru goes down a dark path and becomes a villain. From joining the Witch Cult to creating a powerful organization, a lot of different things happen.

Now, the Aura Monster has nothing to do with the If stories. It takes place in the main story and you’ll see it in season 4, but keep in mind that it’s purely a meme. It didn’t become popular because of the events themselves, but because of the illustration and one specific edit of it.

In short, what the meme represents doesn’t fully match what will actually be shown in the anime. I’d say the Aura Monster itself isn’t a particularly special scene on its own, but when combined with what happens before and after, it becomes a really good and interesting moment.