Square Enix has released a brand new video that reveals the World of Final Fantasy XV that incorporates the game, the Kingsglaive movie, the FFXV mobile game and the Brotherhood anime series. It's a great peek inside the entirety of the universe so be sure to take a look!
The Final Fantasy XV Universe is a project comprised of various content closely related to Final Fantasy XV. The main reason for creating this universe is to provide many avenues of enjoyment before FFXV is released so you have the richest possible experience when you play FFXV (although each piece of the FFXV Universe is a standalone product and does not need to depend on FFXV – each can be enjoyed on their own and vice versa)
While you're at it, here's the third episode of the Final Fantasy XV anime: