One of the core ideas here is that of skill-based magic. That is, the more skilled someone is at a mundane ability, the more skilled they are at its magical equivalent. For this to work, of course, magic can't simply be automatic; it has to have a better chance of working the more skilled the caster is, so the default chance can't be 100%.
Another idea is that, rather than using Vancian magic (each caster has a set number of spells per day; each spell has a level and binds a slot of that level), spells in this system instead tire their casters and potentially harm them. A spell can, using some items from the core system, be overcharged, inflicting more damage to its caster in order to get a stronger effect if the spell works.
The third balancing factor in this system is that spellcasters have fewer skill points and fewer feats. In other words, a spellcaster can do more things with a given skill, but a mundane is better at those skills.
Some characters can learn to cast spells. In order to cast a spell, a character must know the spell in question and must roll a skill check.
Knowing the Spell: Some characters have a "Spellcasting" class feature. Others may have a racial ability that grants them a spell or a feat that does the same. If a character has learned a spell or has something in an ability description stating that they know a spell, they may cast it.
The Skill Check: When casting a spell, a character makes a skill check using the highest of the "Casting Skills" listed in the spell description. Each spell is considered a use of the skill, with the following modifications:
- No auxiliary skills. No ability or skill other than the one used in the casting roll may be applied to the check.
- No magical bonuses. No spell worked upon the caster or the caster's equipment may grant a bonus to the check or negate a penalty. Even spells that directly enhance the caster's own abilities or skills have no effect on the casting roll, unless they specifically say otherwise.
- Common traits. All spells have the following lines in their descriptions:
Trained Only: Yes.Casting Fatigue: After the casting roll, the caster begins to wear out. For every 5 points of DC, fatigue the caster by one factor.
Failure Margin: The improperly handled energies backlash on the caster, inflicting 1d2 damage. Some spells may have other effects that may be used instead of this one.
Margin Rate: 3
Success Margin: Increase the DC of this spell's saving throw by 5. All spells have other effects that may be substituted for this one.
Try Again: Yes. If the spell simply fails, the energies dissipate immediately; if it succeeds, the energies are bound into the form the caster wanted and do not affect other spells unless the spell's description says otherwise.
Armor Check Penalty: Yes.
Saving Throw: Most spells allow a saving throw. The target of the spell attempts a save (DC 10+casting ability+margins of success). If the save fails, the spell has its full effect. If the save is passed, some other effect happens:
- Negates: The spell has no effect on this target.
- Half Effect: All numerical effects of the spell are halved.
- Half Duration: The spell duration is halved.
- Partial: The spell has some alternate effect.
- Reverses: The spell is treated as though it had been cast on its caster by this target, with no save permitted.