As mentioned already, many things about Versus were meant to be in contrast to, "against" what the XIII was doing. Another game inspired by the base lore that XIII used, as was the purpose of the Fabula Nova Crystallis project: to create multiple games under a common mythology (Not the same universe though, which some people erroneously believe). The idea developed a lot but ultimately Versus was meant to be a darker title with action combat from the KH team. A "Fantasy based on Reality" where the world had many familiar elements to real life. While XIII focused on the divine machinations of destiny, Versus XIII was meant to have a more Human spin in it's world and story. Human conflict, a Road Movie story of bonds and discovery, how myth stands up to reality, etc. Noctis himself was developed to have a stronger personality than what Nomura thought was typical, to the point he worried it would rub people the wrong way.
