I’ve been enjoying ICRPG and led a few games with it. But my son threw up his hands in frustration when trying to use the Dire Form only to learn there was only one Dire animal in the book and it didn’t make much sense for a beginner spell.
The magic system doesn’t feel well thought through and I have read many posts on this forum with great ideas to fix it. I here offer my own solution. It is only briefly playtested and probably needs much more tweaking but it incorporates some o the ideas from this forum. I would love feedback or to see other drop in replacement systems.
ICRPG magic house rules
Goals
Magic should be creative - It is not a repetitive set of spells. There should be no spamming fireball and magic missile
Magic should be flexible - It should be a tool for solving more than combat goals
Magic should be spectacular - when needed it should allow the caster to perform truly remarkable feats
Magic must be limited - It must come at a cost and used sparingly. Great magic should come at great cost.
Magic should be dangerous - It is a power that takes great skill not just to access but to control
Rules
There are domains or types of magic. At character creation one is chosen. Some creatures and objects are immune to some types of magic.
Advancement allows acquisition of a new magic domain or an increase in the level of the current domain.
Spells are not required. The caster describes what they are attempting to do based on the type of magic they wield. If they are attempting a level one spell it is roll to cast. A natural 1, they lose control of the magic and the results are chaotic. A natural 20, it is a critical hit and you add ultimate.
*This means that for beginning players the rules are even simpler than the basic system as they aren’t even tied to spells. But they are limited in power. If they want to gain power they have to advance.
Casting higher levels
Casting higher levels requires effort at one heart of effort per level. A caster who applies effort to casting a higher level cannot take a different action on their turn. If they are attacked they just have to take the damage. Hopefully they have allies who will protect them, or cast a shield or something. Multiple magic users can combine effort if the spell narratively matches the domains they are using. At the start of the turn the player decides to apply more effort or cast. If they cast it is a normal cast to roll. A natural 1 is a disaster. They lose control of the magic with much greater power. A natural 20 is a critical hit, they add as many ultimate damage dice as the level.
Level 4 is the highest level anyone has succeeded. Perhaps the DM might allow a caster to go even further in a dramatic moment.
Magical power
Each level increases the power of the previous level. A level 1 spell has d10+modifier, level 2 has 2d10+2modifier, Level 3 4d10+ 4modifier, level 4 6d10+6*modifier. Critical hits add the number of ultimates as the level cast. A most powerful level 4 spell with a modifier of 4 and a critical hit could do 60+24+72 = 156 damage. But that is incredibly unlikely. Average damage for that same situation would be about 30+24 = 54 damage. Still enough to one-shot just about anything. If caster hits 0 xp the magic explodes appropriate to its current level. On average it should take more than 4 turns to reach level 4, but lucky rolls might get you there in 3 turns.
Exhaustion
After casting a higher level spell a caster cannot perform magic for 1, 3, or 5 turns based for levels 2, 3, and 4 respectively.
Domains of magic
This is mostly a flavor item. You could use examples from Magic the Gathering, or Avatar the last Airbender, or D&D, etc. I think a good approach is to have the player define their domain and leave it as a mysterious thing that there may be other domains not yet discovered.
Spells
Spells become more as they should be, a reference for what worked in the past. After a successful spell the player can write down what they did, the level they cast it and the effect it had (this would be in accordance to what the DM agreed was reasonable for that spell level). The user could expect a similar attempt to achieve similar results.
For example:
Heal
Level 1
Restore (1d10 + Modifier of HP)/2
Magic shield
Level 1
Surround yourself or another with a magic shield that absorbs 1d10+modifier damage
Wildform
Level 2
Transform into a really mean bear with 3 hearts. When HP is depleted or when caster chooses reverts to original form with previous HP. After 1d8 turns caster must return to original form.