Rituals are the most basic, accessible form of magic. Rituals may take anywhere from minutes to days to perform, but they can achieve almost any effect. Many rituals require specific foci or components; the rarity and difficulty of obtaining these foci and components increases with the scale of the magical effect.
Spells are magical effects that can be triggered quickly. Unless otherwise specified, all spells require one standard action to complete and do not require foci or components. Spells are more difficult to learn and use than rituals; only creatures with certain racial or class abilities can use spells.
To a wizard, spells are rituals that were deliberately left incomplete but can be completed quickly within 24 hours. Material components and foci may be required during the ritual, but are usually not required when the spell is completed. Wizards need to maintain a low level of background concentration to maintain spells; for this reason, wizards have a limit of how many spells they can have prepared. Also, some effects may cause wizards to lose prepared spells. Wizards can, in principle, perform any possible ritual or cast any possible spell. However, they may need to go through substantial effort and expense to learn how to achieve a particular effect.
To a cleric, spells are gifts granted by a god at the completion of the proper worship, prayer, or sacrificial ritual. Cleric spells do not require components (unless the ritual requires a sacrifice) and a proper altar, shrine, or holy symbol can stand in for any focus. However, a cleric can only cast rituals or spells that are within the domain of the god that the cleric serves. Gods are generally only willing to grant a certain number of gifts to a cleric per day, limiting the number of spells that a cleric can cast.
To a sorcerer, rituals are strange and arcane, but spells come naturally. They require neither components nor foci. However, each sorcerer can only cast from a small list of spells that is unique to that sorcerer. Casting spells draws from sorcerer's TKTK:STAT_OR_POOL, putting a natural limit on the number of spells that a sorcerer can cast in a day.
Spell schools cap out at six levels. Metamagic abilities can raise the level of a spell beyond six.
Anyone can potentially cast any spell using ritual magic. Some simple magic is commonplace. However, complicated magic usually requires rare and expensive foci and material components, putting it out of the reach of most.
"An army? Oh, I don't need an army."
Creating things from nothing. Fast and flashy. Generally only does physical damage. More easily resisted than other schools. Most powerful at low levels, less useful at high levels as resistances become more common -- but still deadly against unprepared targets.
"The legions of Hell have consented to provide me with all of the assistance that I require."
Brings things from elsewhere. They are real, though possibly only temporary, and are thus less easily resisted than evocation. It's a more difficult school, though, that can't do as much at low levels.
"Why, my army of flying monkeys, of course!"
Making changes to things. Spells seem individually under-powered, but stacked bonuses can become overwhelming.
"I'm afraid that your army is of no help to you here. You'll have to make do without them."
Blocking and stopping things. Can shut down another caster easily enough, but actually doing damage is hard.
Remove positive bonuses to armor, weapons. TKTK: don't re-use the term "enchantment".
Turn positive bonuses on armor, weapons into negative. TKTK: don't re-use the term "enchantment".
Become the master of a summoned creature. TKTK: maybe this should be conjuration? Or both?
"Why would I go through all of the effort of raising and supplying an army when I can simply use yours?"
Messing with minds and tampering with others' perceptions.
For the duration of this effect, any spell that you cast appears to originate from the linked creature.
The target believes that the caster is very threatening/vulnerable (as chosen by the caster).
The target cannot perceive up to one creature or object per caster level.
"My army of the dead."
This school has many uses. It can animate the corpses of the dead to do the caster's bidding. It can also drain the life from living creatures, attacking their stats directly. Necrografts are the easiest way to replace lost body parts, though such repairs are usually only temporary.
The easiest way to replace a lost body part, but has disadvantages. Necrografts can't heal naturally and are subject to many spells that affect undead creatures.
Make an undead creature do (or at least attempt to do) something. Intelligent undead (or any other intelligence attached to something undead, such as a person with a necrograft) get a save. Overriding an existing command requires a caster check.
"Your army is already dead. A series of unfortunate mishaps, I'm sure."
Perceiving the imperceptible, seeing things far away, predicting the future, and tampering with chance.
Determine which of a set of tasks the target will prioritize. This can be used to, for instance, determine whether the target will focus on the most threatening or the most vulnerable targets in combat.
"Let your army do their worst. They'll wear out before I do."
Can negate or undo most any form of damage and can bring back the dead. Deadly to undead creatures, but has few options for harming the living. Can also promote growth, create life, disease.
Permanently attaches a new body part to the target. The body part must be undamaged and come from a fresh body. Higher level than necrograft.
Re-grow wounds and missing body parts. High level.
Heals one Stamina per minute for anyone nearby. Low level.