A fan mod has added a full-fledged co-op to Dark Souls without restrictions so that you can have fun suffering with your friends

Dark Souls has finally received a full-fledged co-op mode without any restrictions thanks to the efforts of a modder who previously created similar modifications for Elden Ring and Dark Souls 3.
Here's What We Know
The modder, known as Yui, gained fame for his work on Elden Ring, where he removed artificial co-op restrictions, allowing players to freely explore the world and fight bosses together. A similar mod was released this year for Dark Souls 3, and now it's the turn of FromSoftware's timeless classic, the original Dark Souls.
The Dark Souls' Seamless Co-op mod is already available for download on NexusMods and works similarly to Yui's previous developments. It adds a special item that allows up to five additional players to join your session. Once connected, participants will notice significant differences from the original game.
For example, in the event of death, a player is respawned at the last campfire they visited instead of being kicked out of the session. Clearing locations or defeating bosses also does not break the co-op game. In addition, when one player rests by the campfire, the world state is updated for everyone; NPC dialogues and events are synchronised; all fog walls and barriers that restricted co-op areas are removed, and progress made in the co-op session is saved in your own world.
Yui has also implemented customisable scaling of enemy difficulty in multiplayer and notes that while seamless co-op makes Dark Souls "much easier", the default difficulty settings should provide an enjoyable experience while "maintaining the game's difficulty to some extent". It's worth noting that players cannot instantly respawn during a boss battle after dying - instead, they become observers until everyone in the group is defeated or someone rests by the fire.
Dark Souls' seamless co-op mod, which also supports invasions, is currently in alpha testing and is therefore "very likely" to contain bugs. However, using it will not result in a lockout, as it uses a redesigned peer-to-peer connection system rather than FromSoftware's servers. The mod even creates a separate save file to separate the modded and original game if you want to play both versions at the same time. However, Yui warns that attempting to revert a modded save to the vanilla version will likely result in a lockout.
Source: Nexus