The Rise of Mob Figures In The World Dxd

A man who accidentally transmigrated into the body of a young man named Ryo does not know the purpose of his transmigration but he now lives in a world that he thinks is chaotic. Why? because him current world is a world in Novels where he is just a side character who doesn't even appear in the main story. But that man also keeps getting dragged into the main story, so how can this man who is now Ryo survive the various conflicts that should befall the main character but turn to himself!?.