Shadowdark's Roll-To-Cast System
Thoughts on Shadowdark spellcasting and a tweak I like to run
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Introduction
Good day dear reader! Today we're going to walk through thoughts I've been having about roll-to-cast spellcasting. Those that have been reading our posts here at the Glyph and Grok for some time will know that my go-top system of choice when I am running games is the Arcane Library's Shadowdark. Roll-to-cast is a key defining factor of the gameplay and I have not seen it used in other OSR style games. It has been some time with spinning up my own setting that I plan to use as my default moving forward and now I am running a little "primer" game with some folks to kick the tires and I immediately decided to tweak the roll-to cast system and thought it useful to get my thoughts on this on paper here for any other game masters or referees to use themselves.
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Let's discuss how the roll-to-cast spellcasting works in Shadowdark and walk my thoughts as I tinker with it for my own purposes.
Premise
Coming up with engaging ways to bridge the rules and the context of play at the table is one of those big game mastering skills. In OSR circles, this is commonly referred to as "rulings not rules" which in general I agree with. Previously I've argued that the "rule of cool" is only a thing because modern heroic fantasy games declare every thing must have a rule to be viable and turns them into a tool for the players and is not needed link to previous article Previously wrote thoughts on "Rule of Cool Addiction", but I have an example where I decided to lean into cool to elevate a scene on a whim and it pushed the entire table into a very memorable play experience This is something that can go awry easily, so should be aware of the risks, but with the right players it can be a fantastic injector of fun at the table. You have to be sure, something that is fun for you behind the GM screen can syphon agency and interest from the players at the table. Describe in detail the instance of failing to cast the Light spell in a level 1 game that birthed "Satchey" the sentient Satchel that came into existence and then faded from existence in the span of half an hour.
At the same time, mechanical tenets are needed at the table to keep everyone on the same page, couch expectations, and provide a foundation for reaching to a place where the rulings can build up what ultimately becomes your table's version of the game. So it is always worth exploring new rule sets and sub systems even if just to get examples of how other game masters have translated the idea in their head into mechanically satisfying gameplay at the table.
So how does roll-to-cast spellcasting work in Shadowdark?
Each PC has a spellcasting ability which has it's modifier rolled with a D20 against a target difficulty class (DC) and if the result meets or beats the DC, the spell is cast successfully. It can crit fail or crit succeed garnering possible catastrophe or extra boon from the casting.
Spells in Shadowdark follow an OSR tenet of being majority utility in nature - you're not picking from a wide smattering of damage type options like modern heroic fantasy.
At first glance, I have loved this little system for some time. No "spell slots", no number of casts per day, AND magic feels dangerous while, theoretically, a PC could keep casting all day long if they don't fail the check. Spells are simple, powerful, and there's a randomly applied limit.
How I Run It
Having run this system for some time, I've had a particular situation come up multiple times that has felt really good to tweak: Failure to cast on the first try. It just feels real bad. Especially at lower levels when you fail that very first roll trying to heal someone in your group and it's your expected roll - it just sucks.
Of course there is the argument that if everybody understands the risks and chances and rules beforehand, that's just the way it goes. It may smack of participation trophies and avoidance of consequence - but that's not what it has felt like at the table when I manipulate this to not be a total failure when a spellcasting roll is failed (outside of crit failure of course).
What I’ve been doing is creating a degree to between total failure and total success. If a spell cast is failed, there will be some diminished version of the intended effect (which I will likely have to pull out of my ass) and there are two big reasons I think this just feels better at the table.
1. Players need to have some reliability in their toolkit. This is the main negative I hear about this kind of system, most memorably from Questing Beast for me. OSR styled games expect the players to inject their intellect into the gameplay and some or all of your primary tools have 100% link to a die roll, it changes the play from planning an execution to a roll of the dice.
Example of point 1: I have had the honor and pleasure to run game for some old school hard core gamers that are totally bought in on the 3D6 down the line and rely on player skill and wit and see where the dice fall, and yet when I informed them that they failed the spellcasting check and they now got no effect and lost that spell - it was devastating.
Of course not everyone is the same, but it caught me by surprise and has happened more than once which made me think.
2. This turns a moment that is just a hard negative into opportunity for an interesting interaction between the world and the spellcaster. Leaning into this has led to some very memorable moments at my table
Example of point 2: On a whim while playing for a big group, A player cast the “light” spell to get exploring in a dungeon and immediately failed, and instead of saying it just didn’t work - I asked “What is the most inconvenient thing on your character’s person to produce light at the moment?”
Player: “uhh...my backpack I think, hard to hide if I need to.”
Other Player: “hey we need a way for this guy to join the game.”
Me: “New player is now the sentient soul of this satchel, coming into existence as the spell is cast and unaware of the fact they will cease to exist when the spell duration ends”
Table laughs and we run this gag for the next half hour until “Sachey the Satchel” ceases to exist in a fun bout of dark humor
Takeaways
In my view the best use for reading every new rule set you can get your hands on is to see what mix of play styles that game is presenting and what levers are on the table for adjusting as you will and what effect turning the dials has on the fun your group is having at the table
As I am spinning up my own crucible to battle-test my favorite ideas from all across the OSR to help me create my own setting and possibly my own game, I am constantly thinking about where the weak points are in the “rules” in relation to the types of fun I want to promote at my table.
To that end I have decided to move forward with this as a standard rule for the game I’m running. We use Shadowdark as the base, and the roll-to-cast system that is described within, but when a spellcast check to bring a spell effect into existence is failed, there will be some minor effect from the spell that occurs before that PC loses all use of it for the day.
I believe this just feels better for the caster at the table. I know it is a difficult balance to keep martial classes and caster classes balanced and moving anything in the favor of the casters can be to great detriment of the martial classes, but so far in this experience this hasn’t caused any consternation in the martial players and only makes their support more reliable.
The other side of this coin, is that the NPC enemies using spellcasting will get the same benefit.
I need to see how this plays across the scale of the levels, and maybe there will come a point when this is just TOO powerful when the players have access to higher tier spells, but in the OSR game styling, I think this can create some reliability of kit for the casters without taking much of anything from the martial classes.
What are your thoughts, dear reader?
Thank you, dear reader!
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Till next time!
