Magic is a very powerful combat style with the capability of destroying opponents in one blast. The downfalls are that it takes time to build that power, runes to fuel it, and even then you may miss. Spells come in different Tiers, depending on how much you charge your spell.
Tier 0: (Instantly Fired) This is just a parlor trick at best. A gust of wind, a snap of flame, a drizzle or mist, or a small rock. Better for distractions or stunning an opponent.
Tier 1: (One Round charge) This is your standard attack, akin to a straight-forward blow with a sword. It does normal damage.
Tier 2: (Two Round Charge) This has some oomph to it. It does 2x damage, and has no ill effects on you.
Tier 3: (Three Round Charge) This is the limit of regular mages. This attack does 3x damage, and has no ill effects on you.
Tier 4: (Four Round Charge) This is an overcharged spell. It deals up to 4x damage, but can hurt you for up to 10 damage.
Tier 5: (Five Round Charge) This is the limit of mortal magic. This does 5x damage, and has the potential to hit more than one target. However, if you are below level 10, you take half the damage dealt.
It takes a full round to charge and release a spell. Charging a spell requires a Magic check of 10 + 2x the Tier of the spell that round. So first round charging takes a 10, the second round takes 12, and so on to Tier 5 with 20.
Your spell fires just before your next round, so damage taken between your two turns risks dispelling your spell. You must make a Constitution check of 10 + Damage Taken + Spell Tier to keep it.
Not all spells are created equal. Some are very important or useful, and as such, they deserve special rules.
Disruption Shield is a Tier 3 Spell and requires 3 rounds to charge. This spell nullifies the first hit taken that does damage. It does not reflect anything, it simply makes it so that the defender takes no damage. It is a permanent cast, lasting until the defender takes damage. It has a 10-round (1 Minute) cool-down.
Vengeance is a Tier 3 Spell and requires 3 rounds to charge. Vengeance reflects 75% of a hit back upon the attacker. It does not negate any damage, it just reflects some at the attacker. Vengeance wears off after 1 day if no damage is taken. It has a 5-round (30 second) cool-down.
Shield dome is a Tier 3 Spell and requires 3 rounds to charge. It encompasses a 3x3 area around the caster that protects everyone inside from 50% of damage dealt. It has no cool-down, but for each time it is cast within 20-rounds (2 Minutes) it suffers a 50% drop in protection. (50%>25%>12%>6%>3%>1%) It lasts for 3 Rounds.
Heal Other is a T2 spell that transfers up to 75% of the caster's current health to a single target. The caster is left with only 25% of their lifepoints remaining.
Heal Other is a T3 spell that transfers up to 75% of the caster's current health to targets in a 3x3 area around the caster. The caster is left with only 25% of their health remaining and the 75% is divided as equally as possible among the targets.
Spellbook swap is a T0 spell that allows a mage to use a spell from a different spellbook than they are carrying for one round.
If you are all about preparation, chances are you will have more than one of these spells applied at a time. To illustrate what happens, here is an example where all the spells are in place at one time.