Might represents the physical power of the Hero.
It's the base stat for the Health Points and Strength.
Health Points (HP) represent Hero's vitality. Each hit he gets will reduce this score. If it reaches 0, the Hero is Knocked Out. Food and healing spells restore HP, but a Hero can't have more Health Points then his maximum.
Strength represents how much damage a Hero can do with a standard attack or a physical special attack.