Each hero have a primary attribute depending on the Hero's type (i.e. Paladin, Archmage), the first will give a privilege to the Strength while the second will get a bonus thanks his Intelligence. Each point added to the Hero's Primary Attribute also grants him a '1 damage point' bonus (aside of the other bonuses described below).
Strength
Strength is the measure of the physical power of the Hero.
Hit Points: 1 point of Strength = 25 increase in hit points. Total HPs is calculated from the formula 100 + 25 * Hero's STR
Hit Point Regeneration: 1 point of Strength = .05 hit points regenerated per a second