https://www.gamespot.com/articles/final-fantasy-15s-online-multiplayer-dlc-given-rel/1100-6453466/

Final Fantasy XV's multiplayer expansion will be available to play from October 31, Square Enix has announced. Titled Comrades, the update will allow players to "create their own avatar and join up with three friends to take on epic quests and battles."

In order to play Comrades, you'll need to own Final Fantasy XV and purchase the expansion. For those that own the season pass, Comrades will be available at no additional cost. Of course, an Xbox Live Gold or PlayStation Plus subscription is required to play the multiplayer component of the game.