The latest game form industry veterans Brenda and John Romero got a surprise reveal this week during Nintendo's E3 Direct. Titled Empire of Sin, the (slightly censored) trailer showed off a turn-based mafia strategy game that was also being demoed behind closed doors at Paradox's booth.

Curious about what's got the Romeros (and their teammates) diving into the world of 1920s prohibition, we dropped by for a quick look at Empire of Sin and a brief chat with John Romero. As he explains it, Empire of Sin started off as Brenda's passion project, combining her history of strategy game design with a love for the same historical era that inspired Scarface, The Godfather, and other classic gangster films.

What wasn't apparent in the publicly released trailer was that Empire of Sin isn't just an organized crime simulator, it's also building emergent narrative beats based on the traits and relationships assigned to the player character and a band of recruitable NPCs.

As John explained it, "Adding all of the character traits and relationships adds a whole layer that most games don't have. The fact that it changes over time makes it more emergent. They're not static---you can't just say 'this character is always like this, and they're like that forever, and I know how these chess pieces work together.' The chess pieces change over time."

This means the company is attempting to play in a space where simple gameplay decisions can feed into this trait evolution and vice-versa. Romero and his team showed off one specific example that began with ordering a character to execute a downed (but still alive) enemy. According to Romero, repeatedly ordering one character to move in for these close-up executions might give them a specific bloodthirsty trait, and even put them on the path to being a serial killer.

As that character progressed down that path, other characters would begin to fear working alongside them, influencing who the player sends on specific missions in specific contexts. This system also deals with which NPCs are in love with each other, which ones are enemies, which ones are alcoholics, and beyond.

Watching Empire of Sin at work, it was notable to see a smaller-scale version of systems also being pitched upstairs in games like Watch Dogs: Legion, Dying Light 2, and other games. Romero Games is obviously a much smaller company compared to Ubisoft or Techland, so we asked John what his thoughts were on creating these kinds of emergent systems at a smaller company.

"You have to just have a certain number of relationships, that's why you don't have a million of them," he said "It's a number [the player] can keep in their head and think about. So there's emergence, but it's not off the scale where you can't understand anymore how the game works."

If you're curious about other games from Brenda Romero that inspired Empire of Sin, be sure to check out her 2016 GDC Europe talk.