While Physical Attacks are simply a basic attack vs a basic defense (and then basic criticals), Magical Attacks are reliant on an elemental system.
All magic attacks share the same magic attack property, but the attack itself has an elemental. The attacker also has 4 different magic attack critical rates, one per element. The defender then does not simply have a magic defence, there is a different defence for each element (but with shared magic critical resistances).
Fire Attack Spells form the backbone of attacks for all three magic attack classes, in every case being the first elemental attack each class is made available to. Fire spells also feature incredibly high damage, sometimes at a heavy price. Fire Area of Effect Spells generally are only capable of small areas, as this element is most featured in devastating single target attacks.
Fire Support Spells only appear in the Dex buffs Clerics get, as Fire is not a very supportive elemental.
Water Elemental Spells are mostly found on the Destruction Path of a Sorcerer, yet they are also the primary element of a Light Cleric. Ninja Assassin also gain a few very useful spells from this elemental.
Water Attack Spells are frequently devastating with their additional effects, such as slow (reducing either movement speed or attack speed, but may reduce both) or freeze (typically reduces physical defence). While being almost as impressive for damage as fire on top of this, Water Attack Spells also share Fire's inadequacy when it comes to Area of Effect Spells.
Water Support Spells appear frequently in a Light Cleric as all healing spells are Water Elemental. Additionaly, one of the Cleric's Curse spells are of this elemental, as well as several recovery and magic improving spells.
Wind Attack Spells may not have the high damage of the Fire Element, but they are all highly aggressive spells. All high level Cleric Attack Spells are Wind elemental, including the only Light Path Attack Spell. Assassin and Sorcerer's Wind Spells feature some of the most direct and quick attacks available to the class, including the Sorcerer's only long range area attacks.
Wind Support Spells are mostly Effect Skills with the only exceptions being the Cleric's Mid buff, the Assassin's Movement Speed buffs, and the Sorcerer's Wind Shield and special magic attack buff. Otherwise, the Support Spells include another curse and other debilitation effects from the Cleric (including the Cleric's special trap attack spell) and Mobility influences for the Sorcerer.