In a major departure from previous main series Final Fantasy titles, XV is an Action RPG along the lines of Kingdom Hearts, enjoying tropes such as Implausible Fencing Powers, Spontaneous Weapon Creation, Weaponized Teleportation, taking cover and massive video game setpieces. With nothing but his friends, his father's car Regalia, and the magical abilities afforded them by the Crystal, Noctis sets out to defeat Niflheim, drive back the daemons, and fulfil his destiny as the King of Light. While they are away, the peace negotiations turn out to be a trick - Niflheim seizes the Crystal, kills King Regis, and conquers Insomnia. Noctis departs on a trip to Tenebrae to wed Lunafreya with three companions: Gladiolus Amicitia, his Sworn Shield and bodyguard Ignis Scientia, his advisor and team cook and driver and Prompto Argentum, his best friend. Niflheim approaches Lucis with an offer of peace, a condition of which is that Noctis will wed Princess Lunafreya Nox Fleuret of Tenebrae, a country under Niflheim occupation Lunafreya is also the Oracle, a priestess able to heal the sick and wounded. Niflheim continues their push into Lucis, their eyes ever on Insomnia and the Crystal.
Over the years Niflheim develops technological advances that allow them to press their advantage, forcing the Lucians to retract the Wall to merely shielding the crown city of Insomnia. For decades the expansionist Empire of Niflheim has been at war with Lucis, but while they have conquered most of the rest of the world, they cannot touch Lucis due to the Crystal powering a magical barrier that shields the nation from harm.
In the world of Eos, the Kingdom of Lucis possesses a Power Crystal that affords its nobility magical powers. note Game director Hajime Tabata has stated that while XV thematically remains part of Fabula Nova Crystallis, its mythos has since "disconnected" from the subseries's core structure, and features lore vastly different from that of XIII and Type-0. It is the sixth entry in the Fabula Nova Crystallis: Final Fantasy subseries, sharing a common mythology with Final Fantasy XIII and Final Fantasy Type-0, albeit with no direct connection. Final Fantasy XV, formerly known as Final Fantasy Versus XIII before its rebranding in 2013, is the fifteenth Numbered Sequel in the game-delayingly popular Final Fantasy series.