I just had this random idea. I'm looking for a novel where the MC is not a transmigrator, reborn, had gotten some sort of a system or something that indicates that they're a novel/game character or some accident happened and they remembered their past life where they had read a novel which is the world they're currently at. I'm looking for that kind of type where they're like, "hmm, is it just me or something is off in this world". Then they observes as clues slowly flows in for example: how the world seemingly revolves around one person, whoever offended that person always ended up completely destroyed, etc. and finally reached a conclusion: "Ah, this world kinda feels like a novel". I'm looking for something like that ↑↑↑ I know a shounen ai manga where the main character knew that he's living in a BL world because all the girls in his world don't have faces (or they're blurry) while there's a lot of handsome and beautiful gay couples around him. Since he's a straight man, he read a bunch of BL mangas all so that he can avoid any possible BL scenarios (because the people in that world could literally fall in love with another person by simply bumping into them lololol). Thankfully, he has a "cannon fodder" face so he feels at ease (though he never completely put his guard down considering that his younger brother who also has a "cannon fodder" face were having a BL romance with his handsome blonde childhood friend). Title: Zettai BL ni Naru Sekai VS Zettai BL ni Naritakunai Otoko If there's not enough reference, just think of those games where the characters have self-consciousness and knew that they're in a game. Example: 707/Saeyoung Choi from a game Mystic Messenger (though him being self-conscious was just a fan theory).
I’m The Vicious Cannon Fodder In The Book Mr. Zhou Doesn’t Want to Work Hard Anymore! ^ it's all BL, but it's kinda doesn't fit your description
Akuyaku Reijo Ni Koi Wo Shite The mc is transmigrated in a 5 year old but the original personality of the 5 yr old also lives with him in the same body (kinda like split personality). he realizes that he is living in an otome game when he ends up reading the stupid reincarnated otome game`s heroines notes