The stamina (also known as Mana) bar is a blue bar that will appear at the bottom right of your screen. Some items like magic staffs will consume stamina to use their effects, and the Bull armor, when all of it is equipped, will give you the 'Stamina Master' effect, witch will help you not run out of stamina. The stamina bar only shows when it is not maxed out, and it recovers fairly quickly.
look at the bottom right.
