There is a book for the RPG system GURPS called "Thaumatology". It suggests various minor and major variations on magic systems, and even a few alternative magic systems for that system. One of those major variations is replacing the energy cost (in RM we would say "magic points") for spell with "threshold-based magic", and I'd like to adapt this concept for use with RoleMaster.
It basically works as follows: You do not have magic points, but a "power tally". Every time you cast a spell, you accumulate power tally, and when your power tally is above a certain value (the "threshold", hence the name), casting additional spells is still possible, but it becomes more and more dangerous, to the point of consuming the magic user's abilities and permanently changing the local area or the mage's allies in disastrous ways. Your power tally will slowly decline over time, so your risk of casting with disastrous side effects will eventually be zero again, as long as you keep your discipline. That disastrous effect is rolled up on a table: Your power tally (or a derived value of it, such as 1/5th your current power tally) is added to a roll and then looked up on a table. That table and the dice and all the numbers are, in the GURPS Thaumatology book, suited for GURPS, of course. But I was re-reading that section and was wondering, how would this work with RM?
So, here's my proposal.
Your power point development skill now is used to determine your personal threshold instead. So the lower your level, the quicker you are going to reach the limits of safe casting. Once you are above your threshold, every casting will require you to do a D100 roll + your current power tally minus your threshold, and check on a table such as the ones below.
Example for a Calamity Table
01- 50 – No effect, at least this time.
51-60 – Caster suffers from nightmares
for 2D10 days and will have trouble sleeping.
61-65 – Caster’s threshold reduced by 2d10 for 1D10 weeks.
66-70 – Caster's threshold is reduced by 4d10+10 for
1d10 months. Caster's spells also are cast at -15 for 2D10 weeks.
71-75 – Caster gains 4D10 points of power tally and suffers the effects of a critical spell failure.
76-80 – Caster gains a permanent curse of some kind, related to the nature of the original spell that caused this calamity roll, but only cosmetic in nature (a light spell might cause the caster to have slightly brighter eyes that make people feel uneasy around him or her, a fireball spell might make his or her hair look burned off at one spot, etc.)
81-85 - Caster gains a permanent curse of some kind, related to the nature of the original spell that caused this calamity roll, but only minor in nature, resulting in a -5 modfier to activities related to the curse.
86-90 - Caster gains a permanent curse of some kind, related to the nature of the original spell that caused this calamity roll, and serious, but not deadly in nature. This results in a -20 modifier to activities related to the curse.
95-100 – Caster can no longer cast any spells from the list that he cast to cause this calamity roll. He still has the knowledge, but cannot make use of it.
101-105 – Caster gains a permanent curse of some kind, related to the nature of the original spell that caused this calamity roll, and potentially deadly in nature. This results in a -50 modifier to activities related to the curse, and uncanny events follow the caster.
106-110 Caster gains a permanent curse of some kind, related to the nature of the original spell that caused this calamity roll, andutterly destructive in nature. This results in a -100 modifier to activities related to the curse, and terrible events follow the caster, like ghosts and demons lurking in the shadows for him or her.
111-115 – Roll again with the same modifier, and apply the effects to the caster AND one randomly chosen one of their companions.
116-120 – Caster looses 3D10 points of a randomly chosen stat, both from the temporary and the potential values.
121-125 – Caster is affected by a major curse pf magic. Within 2D10 kilometers of the caster, casting and maintenance of magic costs twice the usual power tally. In addition, power tally does not regenerate down towards zero any more within that radius, and this includes the caster. The effect might wear off after 2D10 weeks if the caster does neither cast nor is affected by any magic for that long a time. It also stops if the caster dies.
126-130 – Caster looses the knowledge of levels in all his spell lists equal to 2D10. This penalty is reduced by 1 per day.
131-135 – Caster looses the knowledge of levels in all his spell lists equal to 4D10. This penalty is reduced by 1 per week.
136–140 – Caster ages by 2D10 years if human, or a corresponding amount if some species that ages differently. This affects him or her even if they are normally ageless. Multiple results of this calamity can turn an elf into a frail doter!
141-145 – A regional curse, like a plague, a terrible long-lasting storm, locusts, spirit haunting or the like affect the area around the casting (from the point of casting to the horizon). This lasts for 3D10 days. There is a connection between this and the wizard that is detectable with appropriate spells.
146-150 – Caster looses the ability to cast spells permanently. There may be exotic magic substances to reverse this, but they are hard to find at the location of the casting and require a long and strenous journey.
151-155 – Caster looses the ability to cast spells permanently as above AND all spells cast in the area (from the casting point to the next major landmarks in any direction) of the original casting now have a minor negative effect associated with them, such as any caster loosing as many hits as the spell has levels here whenever casting any magic, or automatically summon a minor (cat-sized) low-level demon, or something similar.
156+ – As above, but the change affects the whole world! In addition, the caster suffers 1D10 class E criticals of a nature fitting to the original spell.
What do you think?