Frankenstein's monster? Did Mary Shelley get isekai'd too?
This is honestly one of the most confusing mistakes any isekai series can make imo- if the "other world" is supposed to be a game made in our world, it makes sense that the devs might throw in familiar things, right? Except, 99% of the time the implication is at least that the game was brought over to our world by the gods to
lure in suckers screen for heroes (or whatever) & so the only possible reason the holiday is so similar would be that either the gods of the other world liked our holiday's specific aesthetics & copied it, or the other world started the tradition & it somehow made its way here long before the game did, or it's just the world's biggest coincidence that similar holidays also ended up with the same aesthetics despite how drastically different they end up even within our own real world... but then they add in shit like Frankenstein which is even more specific and nonsensical to cross over, & it makes it even more convoluted to try to smooth over that wrinkle, and it ends up only being explainable as "author didn't give a shit lol". It's fine here since it's goofy all the way through, but in some other series it's like "what the fuck was your true motivation here" seeing an author add something that's just disruptive to their own worldbuilding if anyone stops to think about it for any amount of time, lol