Seamless Co-op (Elden Ring)

Please read the full mod description carefully before use. The mod is currently in a beta state, so you are very likely to experience bugs. If you do, please report them to me in as much detail as possible and I'll work to fix them for future versions.

Elden Ring is a huge game, and testing every possible route/combination a party might take through the game is impossible. The purpose of the beta is to pool resources, get as much information as possible, and fix bugs as they arise. Updates to address bugs will be frequent.

Since the DLC update, the mod has been re-written and therefore requires extended beta testing. Please be understanding.

If you are looking for a bug free experience, you won't find it in this version.

About

If you're enjoying this mod, and want to support me, you can buy me a coffee here.

The mod has a discord! (I am not affiliated with the discord)

Seamless co-operative play

Simply put, the mod allows you to play with friends throughout the entirety of the game with no restrictions. With this, it's theoretically possible to play the game from the tutorial up to the final boss completely in one co-op session.

If a player dies, they will respawn in the same world at the last bonfire they rested at. The session will not be terminated.
Defeating enemy bosses and clearing areas no longer sends co-operators home.
All fog walls/barriers that usually restrict the multiplayer zone (along with their respective teleports) are gone.
All players can use torrent (assuming they have the whistle) in a session together.
All map waypoints will synchronise, allowing you to navigate the world in a group easier.
All NPC dialogue and talk events will be synchronised
When one player rests at a Site of Grace, the world state will reset for all players
Game progression events completed in online play will also progress the game in your own world.
You can play with 5 other players in the open world.
An overhaul to Elden Ring's Peer-to-Peer connection system, using Steam's newer networking API

Players are free to explore the entire game map (overworld, underground, legacy dungeons, etc.) together, and may split up if they wish

Quality of life improvements

Along with core function of this mod, there are a number of quality of life improvements that you might like:

As the mod runs the game with Easy Anti-Cheat disabled. You are free to use other mods (e.g. game overhauls) with your friends, provided that everyone in the party has them installed. Please be respectful to your fellow co-operators, and refrain from using mods if they are not welcome.
Frequent disconnections resulting in packet loss and bugs with Elden Ring's implementation of Easy Anti-Cheat are no longer an issue.
A streamlined connection system means that co-operators can join the host from anywhere in the world. So even if you do disconnect, you can very quickly re-join and continue where you left off.

Balancing

This mod undoubtedly makes the game much easier. To try and offset this and preserve the game's challenge, mechanics have been introduced in addition to the base game's enemy health pool increases as you would normally get with increasing phantoms:

You may customise scaling to your preference
If one player sits at a bonfire while others are in boss rooms, those players will be removed from the boss rooms.
Dying during a boss battle or invasion will put your character into limbo, spectating other players until either everyone in the party has been defeated, or a player rests at a site of grace.
If enabled, dying in a cooperative session will afflict your player with rot. Rot is a stackable debuff which will increase with subsequent deaths. You can only remove rot by sitting at a Site of Grace. There are 5 different types of rot, which will be picked at random when a player dies. This has been implemented specifically to avoid one player dying over and over without any downsides, while another player stays alive to keep the enemies from respawning.

Invasions

If enabled in the ini file (allow_invaders = 1) then other players will be able to join your session as an evil spirit and attempt to kill you and your party.

During an active invasion, you cannot warp or use sites of grace to rest. Until you defeat the invader and banish them back to their own world.

If you would like to invade a player, then use the hairpin item in-game, and you will join a random player's session (within your matchmaking range) and be able to engage in PvP.

Can this ban me?

No. The mod prevents you from connecting the FromSoftware's matchmaking servers, and it uses save files different to the non-modded game. Easy Anti-Cheat is also not active when using this mod. There's no way to get banned using this mod unless you modify it with the intent of connecting to vanilla players.

As this mod introduces new items not found in the base game, it uses a different save file to the normal '.sl2' extension. This means that you cannot access your Seamless Coop save files in the base game, and vice versa. Do not revert mod save files back to vanilla save files, as you will likely get banned.

Installation

You do not need any other mods to use seamless co-op. The NexusMods 'Requirements' tab is mods that require Seamless Coop, not the other way around.

Compatibility with other mods has not been tested. You may use other mods, so long as they do not interfere with the multiplayer aspect of the game, or edit any of the items the mod uses to function.

Download the mod from the 'Download' tab or the GitHub mirror

Extract the package you downloaded, and move the following files to your Elden Ring folder (usually in "C:\Program Files (x86)\Steam\steamapps\common\ELDENRING\Game")
Edit "ersc_settings.ini" to your chosen co-op password
Launch the mod using "ersc_launcher.exe"

You don't really have to uninstall the mod. You can use the launcher when you want to play it, otherwise just run the game normally. If you'd like to remove it fully, simply delete the files you downloaded from here.

Within the SeamlessCoop folder should look like this:

Use

You must be signed into Steam, and not in be offline mode to use the mod.

You will get the items required to play seamless co-op when you rest at a site of grace.

You and your party members must be running the same version of the mod and the game to play with each other.

I strongly recommend a secure session password, if a player knows your co-op session password then they can join immediately. The mod use's Steam's matchmaking interface alone in order to engage in multiplayer with others. Note that you must set a password to host and join sessions:

One player must host, and other players must join. You must have the same password as the person(s) you'd like to play with (found in the "ersc_settings.ini" file).

The host must use the "Tiny Great Pot" item to create a session. At that point, the other players can join using the "Effigy of Meleina". You should spawn in at a point nearby the host. Any player can leave at any time using the "Separating Mist" - If the host uses this item, the session will be disbanded and all players will disconnect.

The host can use the "Judicator's Rulebook" at any point to toggle friendly fire and PvP game modes.

When you want to stop playing. Every player (including the host) must use the separating mist in order to close the party.

Troubleshooting:

If you're crashing:

- Make sure you've verified game files with Steam

- Make sure you've tried running the game with ray tracing turned off

- Try running seamless co-op alone without any mods and check to see if the crashing continues

- Try running Elden Ring vanilla to see if you're still crashing

- Try updating graphics drivers

"seamlesscoop\locale not found which has no fallback"

- You need the locale folder in your Game/SeamlessCoop directory. Check the mod description page for installation instructions and try again.

Unfixable:

- "Failed, Steam timed out". This is nothing to do with the mod - there is just no connection to Steam. Remember that the servers go down for maintenance every Tuesday.

- The mod can't fix poor internet connections

I hope this helps. Please understand that the volume of people posting make it impossible to keep up, so I apologise if I cannot answer your question directly.

FAQ

Q) Does this worked for cracked/pirated games?

A) No, I'm also not going to be supporting these versions so please don't make bug reports about it

Q) Isn't this just easy mode?

A) Not necessarily, while co-op play does make the game objectively easier, it's also a completely different way to play the game. There are plenty of "easy mode" mods out that that just give you high health/damage. This mod will be easier but is made in mind of those who want to play the game the whole way through with friends. It has been designed with fun in mind as opposed to reducing the challenge.

Q) Can I modify or redistribute this mod?

A) No, sorry. Please do not modify, repackage, or redistribute this mod anywhere without my permission.

Q) Can I use my save game from the base game?

A) You can, although it would require more work. As mentioned the mod uses separate save files by using the ".co2" file extension instead of ".sl2." Make a copy of your .sl2 file, then change the new copy to .co2. Once ingame, you will receive the mod items automatically. Do not move your save from the mod to the base game, as that may get you banned.

Q) Will updating the mod affect my current playthrough with it?

A) No

Q) Will you make a similar mod for Dark Souls?

A) No

Q) Can you get Steam achievements while using this mod?

A) Yes

Q) I have a question not answered here.

A) If you need more information, or wish to report a bug, have a suggestion etc. please make a post about it, or send me a direct message.

Special thanks

Alpha testers: joby, inuNorii, Emilia, Remyzk, Amirah, Gáté, IshLexi, Hobotam, ibby, HEKTIK, Purpurea, Adopt a Cat, Jouta Kujo, Alpaca

Special thanks to Tremwil for his advice, prolonged assistance and code

Thanks to Oroboro for help with PvP matchmaking tiers.

All the beta testers who played the mod so far, and improved it both directly and indirectly through bug reports, suggestions, and building a community around it. And in particular, members who have provided assistance testing it beyond regular play:

Xiao, Lockheed Martin F-22 Raptor, MegaMaverickX7, CardboardBoxGod, Thirah, Etto, Gacsam, MintedTea, Loki2236, therminatorx, Klesck, Solus and Jim Lahey