The signature die of Dungeons & Dragons, and taller than its siblings, the D20 rolls further because it is the most spherical. The faces are equilateral triangles. The D20 is used any time you want to know if an attempt is successful: attacks, saving throws, skill checks, and ability checks. Each value has a 5% chance. After you roll a D20 to see if you hit an enemy, you will roll other dice to see how much damage you deal. Small weapons use a D4, larger weapons deal D6 or D8 damage, and the biggest deal D10 or D12. D20, The “decider” of D&D dice.