There are Six Primary stats:
Blood: Health. This is most important stat for melee units and the second most important stat for all other units.
Attack: Attack is melee damage. This stat isn't nearly as important as Blood and Defense.
Remote: Remote is ranged physical damage. This is the most important stat for archers.
Magic: Magic affects Mage's damage and Mistress's chance of stunning. Magic also ignores target's defense, which is why blood is so important.
Cure: Cure is the healers stat.
Defense: Defense reduces damage received for units. Defense has diminishing returns; any additional point of defense over 2800 is virtually undetectable. Defense is the second most important stat for melee units and the least important stat for all other units.
Of the six primary stats, with the exception of lords, every unit only realistically utilizes a maximum of 3, and some use less.
The lesser stats are:
Experience: This allows your units to level. Experience occurs with battles and can also be purchased with souls.
Loyalty: Loyalty effects the likely hood of your units to flee from battle. Loyalty starts at 100% and decreases when a unit dies. Levying an area increases loyalty. Levying will not increase loyalty if it is at or above 80. Loyalty also regenerates over time so if you wait for a bit you will regain loyalty.
Tame: Tame is used to show how close you are to breaking a prisoner and making them loyal to you.