The protagonist of the story is a random civilian on modern earth, but then they abruptly die. Either they wake up in someone else's body, in another world completely, or they're reborn as someone else in another world. The former is the standard premise while the latter touches another genre, reincarnation.

They're popular and, as I said, often take place in medieval settings.

[ He still thinks she she's an olde, so. ]

Did you understand any of that?