Natural 7

Designing Nuclear Angels

Over the summer I wrote a one page RPG called Nuclear Angels: The Wasted World. It's free and you can check it out on itch right now. In this post I'll talk about what went into designing the game.

You can also check out a short review/summary by Mint on their blog There's a TTRPG for that.

Game Summary

I made Nuclear Angels for the One Page RPG Jam 2025. The theme for our game was Growth.

The game is about mutated half-Angel, half-Human people trying to either escape or bring about an end to the wasteland they currently live in. As characters adventure, they are likely to gain new mutations through their failures which will help them succeed at future tasks. However, once a character has been mutated too much, they become an angel and must retire their character.

Angels just don't care about mortal business.

The game can be played in a single session or across multiple, depending on your pacing and what you care about. I left lots of open-ended areas, so I expect less improv-focused GMs to do some amount of prep before running the game.

Implied Setting

The setting is a post-apocalyptic fallout anomalous zone. Humanity has been changed irrevocably and mutated entities called Angels walk the world. There is a permanent conflict between Angels and Humans as each side vies for power over the other. Radiation is slowly consuming the world, seeping from a crack in the earth.

I designed a hex flower to use as the game's exploration tool. It makes for very quick and easy expeditions across the wasteland, though leaves a bit to be desired in terms of player choice. Players make dice rolls to randomly determine the direction they can go each time they travel.

It would also work to just let players choose their path. Afterall, the hexes do in-fact represent adjacent locations. Maybe while running the game you give hints as to what lies in each direction the players are curious about. Something like There are train tracks headed south and minecart tracks northwest would work well.

Designing the Wasted World

I had a lot of fun with the worldbuilding in this game. The setting was important to me because of the game jam theme (Growth). All my ideas led me down the path of spreading parasites, fungus, and death. A growing plague of some kind that was consuming the world, or had consumed it already.

Eventually I settled on a post-apocalyptic sort-of-version of Earth that had been destroyed by nuclear fallout. Maybe I had the Fallout games or TV show on my mind, I dunno. Then, because of nuclear fallout, there had to be some kind of strange mutation cutting through humans. This was the birth of Angels. They are people or animals that were mutated so much that they sort of became a new type of creature. Angels are kind of like Violent Mechanisms in the Ultraviolet Grasslands.

I made a list of what I had so far:

This was enough to write the game system, but eventually I had to make some sort of advice for running the game. In my mind this means locations to explore, factions to meet, and situations to get into.

Factions were easy: Humans, Angels, and other mutated things. Locations came with the map. Situations were harder, but I figured I could spark some ideas by giving each faction a good description early on in the game with my Truths of the Wasted World. We learn what the humans want, that angels don't care about anything, and that some creatures aren't interested in Humans or Angels and live elsewhere.

Since radiation is a constant threat, the overall situation of the area is: What do we do about the radiation? What can we do about it is a question to be asked to the different factions you interact with.

By giving the players the goals to escape, survive, or destroy the wasteland I also tried to give the GM permission to use those as catalysts for their own ideas of how each faction wants to deal with the radiation. Humans generally seek to escape it, Angels seek to survive, and other things may want to destroy it.

The Map

The map took a few tries. Making the locations was easy enough, I took a lot of inspiration from the first Dark Tower book and added some monuments related to my list of ideas. However, deciding if I would use a point-crawl or a hex map or a mixture of both was a challenge. In the end I used a hex flower to optimize for readability.

Creating locations was useful to expand the lore. I created faction-based locations for Angels and Humans, then some locations that would feel like opposites of those locations, then some purely neutral locations, then some places that were bad for everybody.

Here's an example of my thought-process:

Oblivion was my name for the crack in the earth from which most radiation spreads. It was probably created by humanity's atomic bombs.

I also tried to cluster "like" locations together for the map, so that each region had a general theme or feel to it. The radiation stuff is on the right, the human stuff is in the middle, and the more Earthly locations are near the lower left. With the hex-flower set up, this means players will experience the transition from familiar (though likely desecrated, corrupted, or otherwise destroyed) locations to odd, post-apocalyptic locations like the city of Fission where humans hide.

Carrying my core themes of growth, radiation, and corruption through each of the locations wasn't too challenging since all I did was name them. Only the core faction locations got a sentence of description: Oblivion, Heath, Haven, and Fission. I tried to use flavorful and evocative names to help GMs describe the other locations on their own. My favorite is Tasken Railroad Company.

Again, if I had more time and space, I would have liked to detail these locations more. Something like what Silver Nightingale did in their Valley of the Shimmering God adventure setting would probably have worked well.

Designing the System

I wanted players to be Angels, or something like them, and I wanted there to be some sort of mechanic for growing your character as you play.

The Inner Conflict

The core mechanic is called the Inner Conflict of Angels and Mortals and it is represented by a dice roll similar to the duality dice in Daggerheart. One dice represents your mortality. Another represents your divinity. They both start as d4s, and they increase their size whenever the other dice rolls higher.

You make this dice roll whenever you take a risky action. You succeed at the task when divinity rolls high, and fail when mortality rolls high. To me, this represents the idea of Angels being super awesomely powerful that they can solve all problems, and Humans screw things up all the time. Ironically, both Angels and Humans are pretty useless in this setting because of how self-centered they are in their goals.

Why did I choose to make the dice increase in steps and what's up with the probability distribution here?

The dice increasing felt like growth and it made it seem like the inner conflicting was changing over time as you could see one side winning over the others. I wanted mortal dice to increase when Angels rolled higher because it feels like the losing side is trying everything they can to win and get stronger. It would be a good idea to try the game where the winning side kept getting stronger too, though you are more likely to get loops of only succeeding vs. only failing. With my rules it's more likely that you'll see a back and forth of success and failure.

The idea of dice rolls changing your probabilities all the time also makes it an interesting decision for whether you actually want to be the one rolling the dice. If you can find ways to resolve situations without tempting fate, you can avoid mutations and becoming a full Angel for just a little while longer. I think this is a good question for players to ask themselves: How quickly do I want to risk becoming a full Angel?

Divine Prescience

This back and forth of success and failure led to another cool mechanic: Divine Prescience. This feature lets you automatically succeed at any dice roll before you make it. You can look at your dice pool, see that you are rolling a d8 against a d12 and decide that it's not worth the risk: you really want to win this time. I've found that instant success buttons are actually pretty fun in roleplaying games, and usually help propel a narrative toward its conclusion when you need it to. Also, if you are afraid that this means there won't ever be any variance or unexpected outcomes in your game, don't worry! You can always introduce more problems.

I wanted to limit how often you could auto succeed though, since doing it all the time is a problem, so I tied it to the amount of Mutations your half-Angel character has. This means that you genuinely are more powerful the closer to being an Angel you are, since you have more ways of automatically succeeding a dice roll.

Mutations

Mutations were another way I implemented the game jam's theme of growth for characters. They physically alter the character's appearance and bring them closer to becoming full Angels (and NPCs).

There is a small table for generating mutations on the fly, but I also wanted people to have free reign of what the new mutations looked like. They really are just cosmetic changes that resemble how you failed or succeeded, like wings or fire breath or a spiked tongue. If I had more space, creating more example mutations would be another improvement I'd like to make.

You gain new mutations whenever the inner conflict reaches a turning point, so whenever a d12 rolls high and then resets. Note that the reset only applies to the d12, so whatever your other die size was remains the same (this makes the game a bit more swingy later on, when you are more likely to be rolling a d4 against a d8 or d10).

Character Creation

All of the other mechanics and rules for creating a character were made to highlight these three things: a conflict within yourself, mutations of your body, and representing Angelic power as the ultimate thing that no one should ever have.

To add some additional uniqueness to characters, I incorporated some character options that add +2 to your divinity die when you roll the dice. These represent special skills you might have, and can motivate you to roleplay in different ways or ask certain questions. I find them helpful to get people started in the conversation.

It was also interesting to decide how many mutations the half-Angels started with. It ranges from 1 to 3, meaning you could be more than halfway to being an NPC right from the get go. Better be careful with how often you roll dice and tempt fate.

Final Thoughts

We looked at how I designed the setting and system for my one page RPG Nuclear Angels, a game about growth and escape in a radioactive wasteland. I tried to use the theme of growth in most of my design decisions, from worldbuilding to game mechanics, and I think it worked out okay. Working with only a single page makes it challenging to completely develop ideas, but I think I have a few new tricks for the next time.

As always, thank you for reading!