In my last article I talked about how to rules shift a campaign from one set of rules to another. In today’s article I am going to break down the steps I used to convert the dystopian future of Underground from its original system over to the new Fate Core .

Straight From The Underground

Underground’s original rule system is a variant of the Mayfair Exponential Game System, which I first encountered in the form of the Original DC Heroes RPG. It’t not a system for everyone, but I rather liked the Underground interpretation of the Exponential system. Overall the Underground rules are pretty solid, and have held up well twenty years later. The main components of the system are the low level super powers, over the top weapons and armor, the mental instability system, and the social change mechanic.

The social change mechanic is the shining gem of the game. It is a system that mechanically models character-driven social change on a number of levels. In essence an area (neighborhood, city, country) has a set of numeric parameters which represented things like: Take Home Pay, Safety, Government Purity, etc. At the start of the campaign these numbers are set. Through the campaign, Players spend their experience points to raise these parameters, creating improvements in the area.

Shifting In 3..2..1..

For all my appreciation of the mechanics, my true love of Underground is still the nihilistic, part-cyberpunk, part-superhero setting. It is for this reason that shifting the game was even possible. As I mentioned in the first article, the reason why we wanted to shift the rules had to do with how the original mechanics were not in sync with how we were playing the game. We were looking for a rules set that would put a bigger focus on character personalities and less on detailed combat.

Using the steps I outlined in the first article, let me show you how I mapped out and executed the conversion of our campaign.


One night, as I was getting set up to play, my players and I started talking about the campaign and how the rules were not fitting how we were playing. We had house ruled a few things to help, but we were playing a different game than what was laid down the rules. Very naturally one of us suggested Fate Core and we all looked at each other and agreed at once that Fate would be a great system for our play style.

Why Fate Core? There were a few reasons. First, Fate has Aspects which tie into the personalities of the characters and create great hooks for driving the story. Second, Fate is as much of a game as it is a toolkit for creating games, with rules for how to adapt any setting, so making the shift would be easier. Lastly, we were all dying to try out a Fate game (i.e. it was shiny).

What’s Important

After deciding on Fate, I took some time alone and thought about what parts of the original Underground mechanics and setting were the most crucial to convert, in order to keep the conversion as true to the tone and feel of the original game as possible. What I came up with were the following elements:

  • Super powers
  • Metagenic Feedback Trauma (aka Mental Instability)
    • Medicine for staving off effects
    • Stress during combat
    • Psychosis
  • Big weapons
  • Big armor
  • Social Change
    • City Stats
    • Improving stats

This list represented the things that were critical when converting, and needed to be fully functional for the conversion to be successful.

Converting The Campaign

The conversion was done in two parts. The first part I did alone. I created a Google Doc and started putting down information just to get my own ideas worked through. After developing conversions for most of the material, I then got together with my players and we went through what I had as a starting point. Then we discussed, modified, and finalized it as a group.

The first area of conversion we covered was character creation. We tried to keep as close to the rules for character creation as possible, but made two changes. The first was reviewing the default Fate skill list and confirming that it would be compatible with the Underground skill list. Where there were differences, we figured out how to address them (via Stunts). The other change had to do with the aspects. The Trouble aspect would represent the character’s psychosis, and the other three aspects would represent their time before the military, while at war, and after coming home.

We decided not to come up with any kind of conversion for the existing characters and just have the players remake them using the Fate character creation rules, with the few modifications we made above.

After that we began to address the list of critical elements. Fate is as much of a game system as a toolbox, like its predecessor Fudge, and with the information contained in the the Extras chapter, we were able to create conversions for Super Powers, Weapons, and Armor that required little additional rules.

We then tackled Metagenic Feedback Trauma, the mental instability that all characters have. Here we extended the existing Mental Stress Track system and used the Trouble aspect. The only extra rules that needed to be added were adding Mental Stress during combat, and how medicine would work. Those rules were modeled from the original Underground rules.

The conversion I was most proud of was the one we came up with for Social Change. We used what is called the Bronze Rule of Fate:

In Fate, you can treat anything in the game world like it’s a character. Anything can have aspects, skills, stunts, stress tracks, and consequences if you need it to.

We decided to make the neighborhood of Jessup Hill it’s own character. We gave it a few aspects, and we took the Underground campaign parameters and turned them into Fate skills, giving them skill ratings like any other character. Jessup Hill was now a type of character, and the neighborhood could be improved in the same way regular characters improve, through the Milestone system. That allowed for the characters to be able to improve the city through play.


I would like to tell you that after our conversion we came back and tested, tweaked, and then rolled out a perfect conversion. No, we were too excited to get started. Instead we took our next session, which I wrote to highlight a few different types of challenges in Fate, and we played our first game.

Shift Complete

With two sessions of Fate-based Underground under our belts I can say that the conversion worked very well. Fate was a perfect choice for our group, and the rules have gone a long way to making the game we are playing more interesting and exciting.

Rules shifting is tricky and its as much art as it is science. With the right rules and some thought a conversion can be easy and accurate.

Last time we asked if you had ever shifted a game. This week, what rules shift, single rule or system, are you most proud of having shifted into a game you have run?