Earth is more vulnerable to spells, and Earth magicians gain magical attributes slower than other elements. Air - Air is nearly the exact opposite of Earth, gaining strength quickly in both attack and defense with spells, but slowly with physical weapons. Fire - Fire is most at home attacking, whether with spells or physical weapons. When it comes to defense, however, Fire is at a disadvantage. Water - Water is, as could be expected, the opposite of Fire.
Water is best at defending, both against spells and weapons.
When attacking, Water suffers a penalty in combat. Each element's spells tend to correspond to the caster's element. For example, many Earth spells affect material possessions, whereas Air spells tend towards invisibility and movement. Similarly, Fire spells generally attack for quick, strong damage. Water, on the other hand, has more spells that do damage over a period of time, slowly wearing down the victim.