You can clone Kelvin and other NPCs in Sons of the Forest with this simple command
The more the merrier.
Sons of the Forest's default NPC companion, Kelvin, is nothing short of a survival game revelation. As a dedicated helper, Kelvin can be commanded to complete menial tasks like gathering sticks, chopping down trees, or snatching fish out of the river with his bare hands. Once he puts his mind to something, he will not stop until asked otherwise. One Kelvin is an unstoppable force. So imagine, then, what one could accomplish with a small army of Kelvins?
You can thank modder CallMeSlinky for making it possible with a mod that enables the debug console in Sons of the Forest (you'll also need this Unity framework mod first). Reddit user jrm850 then quickly discovered that, with some quick javascript editing, you can spawn in as many Kelvins as you want. Once the debug console is in place, you can use the "addcharacter Robby 1" command to conjure a Kelvin (we're thinking Robby is an old name for Kelvin used by the devs). Though, jrm850 notes not to get carried away in the cloning process.
"I can put as many as I want in theory, but if you put too many it can start to cause FPS issues. I didn't experience any real issues with just 4 or less, worked great in multiplayer with other people," jrm850 wrote in a YouTube comment reply.
The extra Kelvins will listen to your in-game notepad commands and even seem to work harmoniously together on building projects. Features producer Chris Livingston spawned in a squad of Kelvins and enlisted them to build a log cabin. They work pretty well as a unit, almost as if multiple NPC helpers was a planned feature at some point. Chris says his only hiccup so far came when one of his Kelvins toppled a tree (accidentally, he hopes) onto another Kelvin, but nobody was permanently injured.
Kelvin and all of his clones remain staunch pacifists, so don't expect extra help fighting cannibals, but the same duplication process is possible for Virginia, too: the command is "addcharacter virginia 1". Virginia will fight with you and can even use guns, so spawning in a bunch will probably make you unstoppable.
The debug console also enables loads of commands and cheats, which is an exciting prospect. Just glancing at the command list, it's seemingly possible to change the weather, spawn in any items, and summon enemies. Of course, be sure to employ these mods with caution: as CallMeSlinky notes, using the debug console "can ruin your game save, so make a backup or be careful!"
Reduce the risk of Kelvin mishaps by not going full Sorcerer's Apprentice on Sons of the Forest, and you should be OK.