Might points represent your current strengths and successes. The number of might points you earn depends on the amount and quality of your units, buildings, equipment items, and heroes, as well as all of your current titles. New buildings, equipment, heroes, and titles will have an immediate effect on your might points, and units after one hour at most.
Might points let you compare the strengths of different castle lords. And if you achieve a certain number of might points, you will earn valuable rewards.