Agility is basically how fast and accurate you are in your movements. A character with high agility attacks faster and more accurately, and Agility helps defend against physical attacks. Low agility, of course, makes you slower and less accurate. An Elf will hit far more often than a Half-Ogre, though a Half-Ogre's incredible crushing blows may compensate. Agility is a component of most skills, and is extremely useful for a thief. A thief with high agility will have very good skills! Again, Agility is a necessary stat for any fighting class, and is useful for magic-users to direct offensive spells.
Charm is a hard stat to pin down -- it is not an actual measure of a person's good looks, but people with high charm are quite attractive to others. It helps with interpersonal relations, such as buying items from store-owners, as a charming person can lower the price of an item substantially. Charm helps in combat, because people are more likely to attack an offensive person than someone with a disarming smile. Charm is a component in some skills, as Charm is not only a measure of a character's charm, but a person with good Charm leads a Charmed life, so to speak, and in general is luckier than other characters. Charm is the main stat for use in Bard spells, and a Bard with low Charm will be a very poor Bard indeed. All characters can use a good dose of Charm.
Health is a character's vitality, toughness, and general physical well- being. Health governs how many Hit Points a character starts with, as well as how many are gained each time a new Level is reached. Poison is less effective on a healthier person, and Health is a component in Magic Resistance. Where Wisdom is the will-power of the mind, Health is the will-power of the body. Health is a prime stat for all fighting classes, but is very useful for all characters, as everyone will sustain damage at some point in their perilous careers.
Intellect is a combination of raw intelligence, creativity, reasoning and basic awareness. Intellect is useful for all classes in respect to their Perception, which is a skill that helps notice hidden and concealed items (and people!). A character with a low Intellect may not notice things very often, such as people sneaking around, robbing them, etc. Intellect is a main component in many skills, and is useful to a thief, but it is vital to a mage! Mages use Intellect as the main stat for their spells. A Mage with low Intellect will be at a severe disadvantage with spells when compared to a mage with higher Intellect. Druids use both Intellect and Wisdom for their spells, so they need to have good levels in both stats. Warrior-types can usually get along without much Intellect, and historically many have done so -- but Intellect is also a component of Critical Hits, so a canny fighter will do heavy blows more often than a dull-witted opponent.
Strength is a measure not just of your raw muscle mass, but also how well you can use that strength. Good Strength adds to the damage you do in combat, and some weapons need a high Strength to use effectively. Conversely, low strength reduces the damage you do. A Halfling warrior may be extremely quick and accurate, but he will do fairly poor damage when compared to a Dwarf! Strength also governs how much weight you can carry without being encumbered. Strength is a necessary stat for any fighting class, but is useful for magic-using classes as well, because no-one has an unlimited supply of magic!
Wisdom is both a measure of the innate connection between a character and the higher powers (whoever they may be), and the character's cool-headedness, compassion, knowledge and willpower. A high wisdom is a must for any Priestly character, as this is the stat they use for their spell-casting. Druids use both Wisdom and Intellect, so they need to have good levels in both stats. Wisdom is the prime component in Magic Resistance, so anyone needing to resist spells had better have a good Wisdom. A Witchunter with high Wisdom would have a formidable Magic Resistance! Wisdom is also used in some of the skills. As for Intellect, a Warrior-type could probably get along with a low Wisdom, but would then be more vulnerable to magic spells.
