Mana represents your mental strength. Making use of abilities that require mental fortitude will deplete your mana. It can also be drained by certain attacks. Should your mana fall below 25% of your maximum mana, then your mind will enter a state of burnout, increasing the time it takes for abilities to come off cooldown for a short while. When you are out of mana, you will not be able to perform most mental actions. You will learn about how to recover mana in HELP RECOVERY.