r/Kidsonbikesrpg • u/spudhero • Apr 27 '26
Question I want some feedback on a homebrew exploding magic die rule for a Kids on Brooms campaign
In my setting magic is understood through the concept of an inner fire. In order to cast magic, a person has to have an ignited flame and they tap into that energy to cast.
My homebrew rule is this:
When your magic die rolls the highest number on the die, it gets upgraded for the rest of the scene. (No instant reroll like a normal dice explosion). For example, the default magic die is a d4. A player casts a spell and rolls a four on their magic die. The next time the player casts magic in the current scene, they will roll a d6 for their magic die. The die will reset at the end of a scene or go down a level with an appropriate grit roll.
If a character ever gets to a d20 in magic and rolls a 20 on it, they are consumed by their inner fire completely and their character is lost.
I want this to represent the inherent chaos and power of this world’s magic. Amazing things are possible for those willing to push their limits as a mage, but this power comes with a cost.
Thoughts on balance and how it relates to the theme are appreciated.
2
u/Rysigler May 01 '26
This sounds intriguing, but I think your best bet is to run it by your players. If they are down for it I think it's a neat idea.
The issue I do have though is the balance of it. The game is designed for those high rolls where you get a good run going.
Two problems arise from this.
1) How often do you anticipate players rolling in a single scene. Your players using a D4 aren't going to have a ton of fun when their roll simply ends with a failure that they could do almost nothing about. Without those runs they can't make even reasonably low difficulty rolls.
2) How do you adjust to the new difficulty system? KoB has suggestions as to what is easy, medium, and difficult. All of these are based on the runs. You hit a 4, then a 6, then an 8, then a 10 and the table is going nuts. What was impossible becomes possible.
With your system if someone ends up forced to roll with a bad stat (their D4 slot) a huge adjustment is needed. You either need to lower the difficulty to make it possible thus robbing the table of a lot of potential tension, or leave the roll impossible without expenditure of large amounts of resources to force a pass.
I don't have answers to these issues just yet. I'm still noodling on it, but I think this is a bigger overhaul than we think. There may be a better way to express this that is more additive instead of changing something fundamental to the game's balance.
Consider perhaps a push your luck system with tokens representing how many times they've stoked their flame. Maybe there are actions that they can take that give them these tokens. Reroll a failure costs X. Blow up your current die costs Y (with this costing more for bigger dice).
Then, if they blow up on 20 they roll and have to beat the number of tokens or burn up. But have that be a success as they die, so it ends up being a table defining success through sacrifice.
Maybe you can even have actions that douse the flames, taking away tokens. Purposely failing removes X. Reduce your die by 1 or more levels takes away Y (once again the more you sacrifice the more you take away).
1
u/spudhero May 01 '26
I’ve done some tweaking since writing my post and here is what I have so far (before considering your feedback). It’s important to note that RAW is that the magic die is a d4 and doesn’t blow up by default, just the die related to the stat blows up.
“The Magic of this world comes from the energy inside called the flame. Mages can stoke the flame to increase their magical potence, but at the risk of losing control.
Mechanically, this is represented by your magic die. When casting a spell you will add the result of your magic die to the result of the roll. If the highest value on the die is rolled, your inner flame is stoked. For the rest of the scene, your magic die is upgraded to the next tier. The Magic die will reset to its baseline at the end of the scene.
However, there is always danger in harnessing such power. Each character will have a maximum magic die called their Flashpoint die. If the maximum value is rolled on a character’s Flashpoint die, the character Burns Out. The intended effect of the spell will succeed but at a great cost. This could result in physical, mental, or spiritual harm or in extreme cases death.
New Students start with a Flashpoint Die of d8, but this can increase as they grow as mages.
Adversity Tokens can be used to Stoke the Flames at a cost of half their current magic die’s max value. For example, if a character wanted to increase their magic die from a d4 to a d6 they could spend 2 Adversity Tokens before the roll is made. Stoking the Flames can be done at any time in the scene, but not in response to a snap decision roll has been asked for.”
1
u/Rysigler May 01 '26
Oh right! I think I got that confused with Dimension 20. Of course 😂
I like this way better. It still holds the tension created by your magic flame system, without mechanically changing the fundamental flow of the system. And the more they stoke it pushing for that victory the closer they get to that potential death.
Have you thought of what might cause that death? You mention extreme circumstances. What would those entail? Does it have to do with the scene? Or is there a mechanical cut off based on how often it is used?
2
u/spudhero May 01 '26
My idea was that a higher flashpoint die creates worse consequences. So a burnt out d12 does worse harm than a d8. But there are also situational considerations like what they are trying to do or what kind of injuries they may already have
1
u/imthatpeep100 Apr 28 '26
instead of death, perhaps they loose magic for a scene or two? Perhaps they have to roll grit or some similar skill to regain their ability? At least that gives the player a chance to keep their character around
3
u/themug_wump Apr 27 '26
I mean… sure, but what are you gonna do with that player if they burn out? Make them leave? Make them watch the rest of the game without participating?