Saturday, November 5, 2022

OSR: Free-Form Magic

I have no idea how coherent this post is.  This is just a few ideas for a Free-Form Magic system, messily splattered onto a page.  

artist unknown

You can cast any spell you want.  Or rather, produce any magical effect you wish, as there are no spells, nor any spell lists in this system.  You do this by declaring what you wish to do to the Referee, who then selects a DC.  Then roll 1d20+COG modifier (or your spellcasting modifier of choice).  If you equal or exceed the DC, you successfully do what you tried to do.

Guidelines for DCs:

Easy: Anything a Mage could do with little to minimal effort.  Unlikely to take more than a few seconds.  Base DC: 5.

Moderate: Anything an experienced Mage could do somewhat easily, while a novice might struggle.  Can take longer, and the longer it takes, the easier it is.  Base DC: 10. 

Expert: Anything a Master Mage could do easily, while all others would struggle.  Often paired with teamwork, artifice and ritualism.  Base DC: 15.

Magic Attacks:

According to the rules described here, characters do not make attacks against a static AC, but against the opponent's roll.  An Atk roll is calculated as 1d20+damage dice+Atk modifier.  A Defense roll works the same way, but is done in reaction to an attack being done against you.

For Magical Attacks, I would set the DC for a 'hit' as the opponent's Defense roll.  This will be for attacks meant to target one creature.   

If an attack does something that cannot be physically blocked or parried, or targets a whole group, the Referee would instead have the targets make a Saving Throw and possibly give them a bonus or disadvantage to their saves, depending on how easy or hard what the caster is trying to do is. 

To calculate damage, I would have have a spell do a base amount of damage, and then let that amount be augmented through the use of dice.

As an example, offensive spells do 1d8 damage as a base. 

If cast with 1-2 MD, they do 1d8+[dice] damage. 

If cast with 3 or 3+ MD, the spell does 1d8+[sum] damage.  


Blasting someone with a ray of ice.  The Referee rolls a Defense roll of 11.  That's the DC.  The caster rolls to cast the spell and gets a 12.  The spell hits!

Shooting a fireball into a group of enemies.  The Referee decides since these enemies are pretty weak, their usual save is an "8", but that's a bit low, since the caster is trying to target a number of enemies.  So the Referee sets the DC as a "10".  The caster rolls a "19".  The spell is successfully cast and all the enemies take damage.


Lower the Difficulty If:
- The Mage is well-rested, unhurt, in prime condition
- The Mage is under no stress or pressure
- The Mage can take their time
- The Stars are right
- The casting is part of a ritual
- There are other Mages helping with the casting

Increase the Difficulty If:
- The Mage is seriously injured, drunk, drugged or mentally impaired
- The Mage is operating under a time limit/running out of time
- The Stars are Wrong
- There was no time for ritual preparations or safety protocol
- There are other Mages helping with the casting, and they're screwing it up in some way

Other Modifiers:

Players can lower the difficulty of their castings by including certain conditions.  For example, if the player wants to include the ability to save to take half damage, this would lower the damage of a spell. 

Conversely, if the player wants a spell to not have any way to defend against or have some other dangerous effects on top of the "normal" effect, that can make things harder for them. 

So if the player wants to throw a fireball, but has been rolling poorly, he can tell the Referee "And if they succeed on a Save, they take half damage".  The Referee should then accommodate them and lower the DC. 

Or if the player has been rolling really well and wants to take a chance, he can tell the Referee, "This is an instant death spell, so if he fails a save, the enemy just dies, no matter how much HP he has left."  The Referee should feel free to raise the DC a bit if the player makes such a request.

from here

Parrying and Reflecting Spells:

Two optional abilities you might want to include:

- Parrying spells

This works like my Active Magical Defense post.  This is something I've almost never used as players rarely have the spells to counter an enemy's magical damage and vice versa, unless I deliberately arrange for something like that in a way that doesn't make it seem like the Referee is deliberately targeting you. 

- Reflecting Spells

When someone throws a spell at you, you can try to 'Catch the spell'.  You do this by trying to match or exceed the DC of the cast spell.  If you succeed, you 'catch' the spell and then can redirect it against any target you choose, as long as they would be a valid target for the spell, as if you were casting the spell for the first time.  Might not be appropriate for all systems. 

Spell Misfires/Chaos and Corruption:

When I came up with my Telekinesis rules in Black Science Superheroes, I added the rule that Tekers gained extra Mana Dice once they reached a certain level of power.  The Telekinesis rules work similarly to the Free-Form magic, so the rules for that can be ported over.

So, Mages gain Mana Dice (MD) as they level up.  They can add these to any d20 roll they've made to cast a spell.  So the more dice you add, the more powerful the resulting spell. 

But, to keep the game halfway balanced, Chaos and Corruption still applies. 

Roll Doubles on your MD and you trigger Chaos- the spell still goes through, but an additional magical effect occurs. 

Roll Triples on your MD and you trigger Corruption- the spell fails, and something happens instead. 

If Doom Points are a factor, then Chaos gives you 1d3, while Corruption gives you 1d4. 

Dooms occur at 10, 20 and 30 as per normal.

by zhu liu

Optional Rule: Aspects

If you're scared of letting players totally off the leash, you can add the following rules.  When a player makes a Wizard, they gain control over one aspect of reality and can control that innately.

Players can only control that one aspect and it's various sub-effects.  This will incentizive more clever thinking, possibly.    

Example Aspects:

- The Elements: Fire, Water, Earth, Air, Lightning, etc.
- Radiation
- Sound
- Time
- Space
- Force
- Emotions/Charm
- Mind/Thoughts
- Life
- Death 
- Luck/Chance

Players could also choose a lesser Aspect, in return for some sort of additional bonus at character creation.  Lesser Aspects are sub-domains within one Aspect.   

Example Lesser Aspects:

- Metal
- Dough/Baked Goods
- Yarn
- Bone
- Smoke
- Marine Animals
- Music

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