VDS inspired Spellcasting system for OSE or other RPGs



Greetings, programs!

I like when you roll to cast, but for me it feels a little too similar to a melee or ranged attack, and I want the spell to be a whole different feel. I derived a spellcasting system from VDS’s skill system, because I think it’s great for what I want to achive with a different but simple to understand system.
We had our first live-test with my group, and it went pretty great. I’m sure it needs some refinement, but I think the basis is solid.
I thought I share it here, maybe others with similar thoughs can get some inspiration aswell. :slight_smile:

The rules in bulletpoints:

  • At 1st level you get 2 spells.
  • You can acquire a spell through learning, scrolls, books, research etc.
  • Spell have their own level (own dice pool). They level individually.
  • Initially every spell has 2D (2d6) dice pool.
  • When you cast the spell, you roll the dice. 1-2-3 are failures, and 4-5-6 are successes.
  • The Effectiveness of the spell is measured by how many die succeeded. Lot of DM discretion.
  • When you roll for a spell and all of the dice are successes (4-5-6), you stripe a mark after your spell. If who have 5 stripes, your spell levels up, giving 1 extra die to the spell’s pool. Note: every die has to be success, so after every level it will be harder and harder to level up your spell)
  • The maximum dice pool of a spell is 5D (5d6).
  • Every 1 rolled after the first one cause a miscast:
    • Miscast 1 - two 1s: minor mishap (like you can’t cast this spell for 1 turn, or you drop your wand)
    • Miscast 2 - three 1s: major mishap (I created a miscast table with random effects, like you become frightened, stunned, can’t cast spells until some rest etc.)
    • Miscast 3 - four 1s: catastrophe, this is when shit hits the fan (the spell explodes in your hand, you cast the spell as critical to your friend, you die etc.)

Additional rules to consider:

  • You can create spell specific tables like –
    • Fireball: Miscast 1 - Caster creates a gust, knocking her prone, DEX check, or SPELL save; Miscast 2 - Light explosion, everyone NEAR becomes blinded, Miscast 3 - The caster is the center of the explosion and maximum damage
    • Polymorph: Miscast 1 - Caster grows slimy scales; Miscast 2 – Own hands are polymorphed can’t cast or use object, Miscast 3 - The caster turns herself into a chicken
  • If you roll a 6, it is a success and you can decide, if you want to re-roll the die once (note, that the result can be a 1)
  • Narrative difficulty: the player wants to use a spell to a harder or unorthodox task, you can increase the success level (e.g.: only 5-6 considered successful rolls)
    • Example: ‘I want to collapse the tunnel with my 4D fireball’ – ‘OK, rolls 4d6, you need to roll three 5’.

Example of play:

  • 3D Fireball.
    • The rolls are 2, 5, 5. The success level is 2 (I narrate what happens, for example it will deal 4d6 damage (2d6/success level).
    • If he rolls 1, 1, 5, for example he will deal 2d6 damage, but burns his hand and can’t cast for 2 rounds)
  • 5D Polymorph
    • The rolls are 1, 2, 2, 5, 6. The success level is 2, and she decides to reroll the 6, rolls 4, so the success level is 3. She polymorphs a stronger enemy to a medium sized creature, or if they’re fighting a horde, then turns 3 goblin to rats (DM discretion).
    • The rolls are 1, 1, 1, 5, 6. The success level is 2, and she decides to reroll the 6, rolls 1! She turns into an eagle with 1 INT, forget her identity and flies away into the skies.

Feel free to share some constructive criticism or any idea about the system. :slight_smile:


I’m not a progr… bzzdddd! -System Malfunction-

My reaction: Sure, why not? If it works for you and your table, go ahead. It doesn’t seem to gel well with vanilla ICRPG but that’s neither here nor there. Your system is very usable and consistent but it has too many moving parts for my taste.

The deal breaker for me is the dice pool mechanics. As much as I love rolling dice - and rolling a handful of them is certainly fun, I don’t really like dice pool systems because I find them slow. Slow to gather the correct number of dice, slow to roll, slow to count successes/failures etc. In contrast, D20 is very simple at its core (unless you are playing Mathfinder ™ :exploding_head: or something); roll, add your bonus, compare to target and move on.

I only bring this up because here we mostly play D20 systems.


It doesn’t seem to gel well with vanilla ICRPG but that’s neither here nor there.

My impression of ICRPG is that you can do anything you want. XD

I agree that dice pools are just too darn slow, but I can also see an argument in making casting spells a tad different than just a D20. Still, a dice pool isn’t all that different than a single die in my opinion, so that idea isn’t my thing for sure.


Thank for the reply! Clearly understand why it isn’t your apple. :slight_smile:
I have to admit, the system I use it in is OSE. In OSE there is a dichotomy at the ability and saving throws (roll under and over). And that way we want to create an other: d20 for ability and saves, d6s for spells (and maybe skills).

For ICRPG (my go to game when playing with younglings) I would also prefer the d20 + target approach for every task :slight_smile:


Here’s an idea though, tell me what you think: to make magic different, I think we should give it a couple of levers to make it feel different. What about another die alongside the Target Number die, a dedicated Heart, and variable resource spending?

The Burn die

This is a D6 you keep next to the D20 you use for the Target Number, and represents the chances to burn spells. The GM is in charge of this die as well, starts at 1, but may clock up to 6.

When a player rolls 1D20 to see if casting a spell succeeds, he better not roll below the number on that Burn die otherwise the spell blows up in his face!

Even on a success? Up to you, or bring back crit confirmation from old-school D&D for an added layer of excitment?

Dedicated Magic Heart

Characters now start with a red heart (HP) and a blue heart (Mana, or whatever other name you want to give it) with a value of 10 each as usual. You can tie the usage of magic items to that blue heart if you want.

Variable resource spending

When a spell explodes in the face of a wizard, roll the dynamic die (page 80 of ICRPG Core 1.3) and substract the result from the blue heart of that wizard. The new total of the Burn die is now the result to avoid on a D20, remember that spells, situations, etc. can play with the Burn die’s amount just like the Target Number to make things exciting and interesting!

When a blue heart is empty, the magic-caster can’t cast spells until his blue heart is replenished.

And just like in D&D 3.5, I like for magic-users to only be able to recharge or change their spells at a specific moment during the day like noon, midnight, dawn, or whatever. Up to you though, that’s just a particular suggestion of mine to keep things interesting.

What do you think? :grin:


I tried the Burn Die, it’s pretty neat! Thank you! Resource spending and monitoring is not out cake, but what you wrote is cool. :slight_smile:


I’m really happy you took the time to try it! And I’m glad you had fun with it! :smiley:

If you had to change it, how would you make it better?


It is good as it is :slight_smile: Just my group is struggling at monitoring resources. Items and HP is more then enough for them :smiley: But I think it’s a good system especially for tactical players. :slight_smile: But the Burn die mechanic is a thing what I think I could at any table :slight_smile:


That’s understandable, nice of them to have tried it as well!

And thank you for your feedback!

Roll fun, friends! o7


whoah that’s defintly much more detail than any VDS skill…