The second prince story is an Isekai(going to another world) , so the MC created the original him who was an average office worker(modern world:Korea) that came from her world and reincarnated into the second prince in the fantasy world. His soul came from the cave which is the way back into the MC world.
Remember, he’s still a fictional character but he knows modern things like an iced americano and TVs because he’s from a fictional modern south Korea which is the same like the real life south Korea.
I hope that kinda cleared that up??
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Don't tell me he's also from our world??
I mean I don't really get it, does he know what an iced americano is? Or is he just wondering, knowing the mc isn't from this world(or country whatever)? I'm so confused rn