D20

The d20 (twenty-sided die) is the most important die. It is used for attack, check, initiative, and save rolls (also known as d20 rolls), which are the four main types of rolls in the game. If an effect affects a d20 roll, it affects all of those four rolls. These types of rolls determine success or failure on an activity and its associated actions and tasks. The higher the result on the d20, the more successful the activity.