Mana

The ability to cast a spell depends not only upon you knowing (and being powerful enough) to cast it, but your also having the energy to do so. Mana is a reflection of how much magical energy you have available to you at any given time. A caster begins each day with mana points equal to his caster talent level multiplied by 10 (e.g. a level 8 arcanist starts the day with 80 mana points). This is called a mana pool. You can cast a spell only when you have enough mana points remaining in your mana pool. There may be ways provided by your game master to expand and/or recharge your mana pool during the game day, such as magical items or potions. Mana may be referred to by a different name depending on how your GM has styled his world and game, but it will, in essence, work the same.