It's not like he's the only one from another world They all are
Bruh. You should re read
People are coming from the other world in batches, it surely isn't that.
I do believe it's something that he saw on the diary or on that temple where he met the monarch's servant, tho, or maybe he can even read it because of the power the monarch bestowed him with.
Ahhhh your probably right because every time he has that reaction it’s something from the book ┗( T﹏T )┛
I read so much stories like this one and I’m just guessing but I’m pretty sure the writing is Korean/ the writing he used in his past? But I’m not sure since they also came from the modern world (╯°Д °)╯╧╧