No idea how many years ago, there was a novel-based anime called Humanity Has Declined (人類は衰退しました). The premise: humanity has declined for unknown reasons, the world is overrun by “fairies,” and the female protagonist, a human, observes and interacts with them. Your standard anecdotal setup. I never read the original, so I can only talk about the anime, and honestly the anime was pretty good. After watching it I was left with three impressions: fun, sci-fi, and what-the-hell-did-I-just-watch. That last one sticks with you the most. You always get the sense the show is “hinting” at or “allegorizing” something, but you can never find the exact parallel, so it’s hard to pin down the author’s stance or viewpoint, what the story is trying to say, blah blah blah. But that’s exactly the appeal of Humanity Has Declined—if it stated its position too clearly, it’d feel like force-feeding you opinions, and it’d be harder to provoke thought. That half-hidden, “still holding the pipa behind the curtain” feeling is just right. And what’s worth noting: the author of Humanity Has Declined is Tanaka Romeo. This was the first and only time I’d encountered his work. I had no interest in what he wrote afterward and didn’t follow him much. Then a while back, a game called Waka-sama no Zasu Sekai (和香様の座する世界) came out, and I saw that familiar name in the script credits again: Tanaka Romeo. And it reminded me of Humanity Has Declined.