Elden Ring technically does allow cooperative play. You can summon other players to your game (or join them) to adventure together. The summoning process is unfortunately just too contorted and downright limiting.
While developer FromSoftware has no plans to better its multiplayer support, there is a modder out there who intends to change all of that by giving players a more traditional and straightforward cooperative experience in Elden Ring.
In a new YouTube video published on the weekend, modder LukeYui announced that his “seamless co-op mod” will become available for public testing later this week on May 27 through Nexus Mods.
The seamless co-op mod will support up to four players in a single party with shared and synchronized progress, meaning that you and three of your friends can essentially play Elden Ring from start to finish.
There is a little caveat regarding shared progress though. The progress to be shared must be made after you join a party. If you create a new character and join a party to defeat an endgame boss, that boss alone will be dead for your game world. The progress your party members did before reaching the boss will not be shared with you.
Items will be unique to each player. There will be no need to roll a dice to decide which player gets specific loot. If a boss drops a talisman, every player in the party will receive the same talisman.
The mod will not connect to the official matchmaking servers. Hence, you do not have to worry about FromSoftware banning you for breaking any terms of conduct. The same goes for the anti-cheat. The mod uses a separate launcher that runs the game without Easy Anti-Cheat.
Furthermore, forget about invading others as a party of four. The seamless co-op mod will not support invasions. You can, however, duel your own party members.