During Sony's Press Conference, Ubisoft unveiled that Far Cry 4 will include a co-op feature where the second player doesn't need to even own the game, in order to join in. How does this sorcery work? Eurogamer got the scoop.
Gamers without the game will have the chance to download a client. Owning this client will enable players without the game join those who do. This client will have all of the game's content, which will make the app quite large, though it won't contain any of the main story missions, since those are tied to Single Player only.
The second player who joins the game will play as Far Cry 3's Hurk, which means that Far Cry 4 could potentially be set in the same universe as Far Cry 3. Ubisoft is notorious for dropping various clues and hints that the games are all part of one big Ubiverse, so it's not that surprising.