Narou is short for "Shousetsuka ni Narou" which is a popular site for aspiring novel writers to upload to. Things like Arifureta, Death March to Another World and Isekai Cheat magician all began there, but also things like Konosuba, Log Horizon and Rising of the Shield Hero too have roots in that site. It's one of the world's largest hosts for webnovels, where companies then pick out some of them and publish them as Light Novels which can then get manga adaptations.