Inzoi is creating a newfangled life sim NPC that can 'grow and develop its own personality' with Nvidia's AI tech

Upcoming life sim Inzoi is launching in early access in March, meaning that Krafton still has plenty of features it's hoping to add to the simulation even after players get to go hands on with it. During CES this week the developers announced a partnership with Nvidia to use its "Co-Playable Character" AI tech to populate the game with "Smart Zois" who adapt and respond to the world according to their personalities.

Nvidia's demo video on the Smart Zoi system walks through the day of a character with a "considerate" personality showing how they might independently decide to help someone lost with directions or give food to a hungry stranger. Then at the end of the day the Zoi adjusts their own daily schedule of activities based on the experiences they had that day.

I admit there is a real allure as a life sim player. Over years with The Sims series players have sussed out so much under-the-hood logic that the idea of a sandbox with simulated characters who could actually do something we don't expect is pretty exciting.

Inzoi's game director Hyungjun "Kjun" Kim shared some of his own thoughts on the tech in the game's official Discord server yesterday.

"Traditionally, NPCs in games operate using a rule-based system, where their behaviors are entirely scripted and predictable," Kjun says. "However, as we continued to evolve this system, we were able to partner with NVIDIA to incorporate an on-device AI solution known as Small Language Model (SLM).

"With SLM, these new 'Smart Zois' gain an extraordinary depth. They can develop inner thoughts about interactions and situations they’ve experienced, creating additional layers of insight about themselves and other Zois. By embedding this AI into their behaviors, we’ve created Zois that act with individuality, which not only makes their actions feel more natural but also adds a deeply immersive element to the inZOI experience."

Presumably this means that your Inzoi save could surround your played Zoi with other characters constantly changing and adapting in a way that feels more lived in—something that The Sims has tried to achieve with its Neighborhood Stories feature.

Kjun says that the end of day adjustment feature already works "remarkably well," adding that "it’s a joy to see a Zoi grow and develop its own personality, becoming more distinct with each passing day." He does otherwise note that the AI will sometimes produce wonky results and that optimization of GPU use is still needed.

Also worth spotting is that Inzoi will detail the reasons that a Smart Zoi made a particular choice, like: "Calmly offering directions to a lost person with clarity and empathy is well-suited to this considerate Zoi."

The explanations for actions shown do all still have that immediately clockable AI cadence that sounds like a student thesaurus BS-ing through an essay for a book they didn't read. That does make me wonder if Smart Zois will be reactive in a way that's actually interesting, or if it's just a more computationally intensive way to achieve the exact same weirdness that sandbox life sim NPCs have always had.

It is generally an interesting mashup of what we'd have traditionally called "AI" for NPCs with a generative text model. Of any place to try it out, a life sim seems like a good candidate—though Krafton is also experimenting with AI PUBG teammates. It's not the only way that Inzoi is experimenting with AI either. The dev team demoed generative art features for creating clothing patterns and a way to turn photos of objects into 3D game models to decorate with.

As for what the feature will look like at launch, Kjun says it may not be fully implemented yet and that Krafton is considering giving players the option to test it as an experimental feature.

You can catch up on more tech announcements and other news from our team on the ground at CES 2025.