A group of modders successfully created a Breath of the Wild multiplayer mod for PC, following a $10K 'bounty' put out by YouTuber PointCrow about a year and a half ago.

　　PC Gamer spoke with the modding team about the effort, which is even more impressive since it can be considered to be a sort of elaborate hack. Modder AlexMangue said:

　　We didn't really use the game code on its own a lot as Nintendo ships them without any symbols and therefore it is not really readable, so we had to do some hacky things to make it work. The main part of this is similar to how cheaters work on other games. We inject our own code into the emulator and therefore have access to the information saved on the RAM of your computer for the emulator process. With this, we look for certain information in the memory, such as the player's position, rotation, etc. This is the extraction part of it, just obtaining the data needed to send to a server we coded.

　　After the server obtains the data from each player, it then analyzes part of it and relays it to the other players. Here's where the hacky thing starts. We are actually using NPCs from the game and making them look like Link. After we spawn them, we just look for the same information we looked at before but for our NPCs and with this we change their position, rotation, etc.

　　According to AlexMangue, PointCrow didn't just provide the monetary incentive to build the Breath of the Wild multiplayer mod (the aforementioned $10K and more afterward); he also offered his own ideas on the creative design. As you'd expect, PointCrow immediately published videos of the mod on his channel, racking up millions of views. However, Nintendo quickly showed it was not too happy about it by blocking the videos' monetization with a copyright strike.

　　Incredibly disappointed that @NintendoAmerica has decided to block my videos on Breath of the Wild. It’s the love for the community and the innovation that we bring to it that has kept it alive & brought new people to love the Zelda series. I hope you reverse your decision soon. pic.twitter.com/CtvjpmBrs3

　　— eric pointcrow (@PointCrow) April 7, 2023

　　At any rate, the Breath of the Wild multiplayer mod (based on the Cemu WiiU PC emulator) is freely available to anyone. The installation process is fairly complex, though, so you'd better check out the below tutorial made by one of the modders.

　　There are no tethering limits to the Breath of the Wild multiplayer mod, so every player is free to explore Hyrule as they see fit. It has been tested with up to nine players logged in at the same time, though the theoretical limit is thirty-two. There are some limitations - for example, the mod doesn't currently synchronize the AI state of the NPCs, so different players may see them doing different things. Of course, there are many plans to improve it, as you can read in the public Trello roadmap. The team also has ideas for additional game modes, and the mod will become open source in the next few weeks. If you wish to support this endeavor, consider backing AlexMangue on Patreon.

　　The Breath of the Wild multiplayer mod is but one of many mods created for Nintendo's acclaimed open world game. Right now, though, most Legend of Zelda fans are squarely focused on the imminent launch of the sequel, Tears of the Kingdom, due to be released on Nintendo Switch on May 12th.