Adventurers, for obvious reasons, never tell.
Landers, very conveniently, never ask - or never ask too much.
Not even the ones depicted as knowledge-hungry.
Not even when Adventurers let slip terms such as "NPC", "real life/world", "game", etc.
Yes, Landers can be very curious sometimes, but I don't remember hearing them asking embarassing questions about the Adventurers' world, questions that may lead to the unspokable topic. Not even Regan, Lenessia, or
Are there, in the Log Horizon franchise, Landers which [discovered | were told | figured out | whatever] about Elder Tale?
Do some of them know the "uncomfortable truth"? I.e. that, in the world where Adventurers come from:
- "Adventurers" are not "Adventurers" at all, they don't have special powers, they just played a game in which they killed monsters for fun, sitting on a chair and clicking buttons on a machine
- Theldesia is just the fictional setting of that game, where Landers are fictional, computer-controlled characters.
It would be interesting to see how they reacted to this shocking revelation.
Note 1: I only watched the two seasons of the "Log Horizon" anime. If the answer would contain spoilers for additional material, please direct me to that additional material (if it is available in English, since I don't speak Japanese).
Note 2: just realize that "Adventures don't treat us like real people" is necessary but not sufficient for what I'm looking for. This because realizing this is not so hard: in fact, before the Catastrophe, Adventurers did not look like real people to the Landers as well (so probably the "Welcome to the village of Arb" joke in season 1 episode 5 could be true also from the Landers' POV). I'm looking for at least a Lander who knows something like "Adventures don't treat us like real people because they used to see us as fictional characters in a game, the so-called heroes were just playing make-believe to escape boredom". This is a completely different animal.
Note 3: The fight between Papus and Elias Hackblade goes near to what I'm looking for, but I still don't think that's what I'm looking for. Papus says to Elias that he (Elias) is fictional, Elias is horrified, but it's not clear if he's horrified by the revelation, by that ugly monster or by the magic the monster he's casting on him. Anyway, Kanami treats Elias as real, but then the scene is cut and we don't know what happens next (at least in the anime). According to the wiki entry for Papus (beware of spoilers!!!), he has a special power that causes Landers to believe they are fictional. I don't care about what the Genius think about Landers, and I don't care if Landers are fictional or real people. I care if there are Landers who will believe what the Genius say, and if this will bring them to discover that Adventurers were just roleplayers, and how this will change their relationship with Adventurers. (Note that Elias is a perfect example of Lander that did not react or ask questions when Kanami and her friends used words like "NPC", "playing", "game", "real life", etc. No, I don't think he already knows the truth about Elder Tale just because he's on the Elder Tale box).