Constitution or Con is defined as "the physical character of the body as to strength or health". This trait has been adapted as a Shadowbane stat responsible for a measure one's health and stamina. A high constitution score ensures that a character can endure more punishment before dying.
Role in Health And Stamina
Granted Health and Stamina from levels 1 to 10 can be calculated using the following formula(1):
((Base Class Health Value / 3.333)*Level) + ((1 + (Level * Base Class Health Value / 200)) * Constitution)
No formula is known for post-class promotion health and stamina scores, but they are affected by the class you choose.
1. Constitution formula: HP, Stam, and Mana formulas (UBI Forum)