- d20 redirects here. For the game system, see d20 System.

Polyhedral dice: d4, d6, d8, d10/d100, d12 & d20
Dungeons and Dragons, on which NWN2 is based, uses die rolls to determine the outcome of many events. With NWN2, dice are no longer rolled on a table, but they're still used throughout the game.
Notation[]
Die rolls are written as XdY.
- X = represents the number of dice rolled
- Y = represents the highest face-value of the die (the lowest value is 1)
For example, 4d8 means four 8-sided (values between 1 and 8 inclusive) dice are rolled (giving a weighted random number of 4-32).
When the number of dice is not indicated, it means one die is rolled; e.g. d20 means 1d20.
The d100 is sometimes written as d% or d00 and is also referred to as percentile dice.
Common types[]
Tabletop DnD uses polyhedral dice. The d20 System -- the underlying rules used by DnD and NWN -- is named after the d20 die. The d20 is used with many of the most important rolls in the game: attack rolls, saving throws, skill checks, ability checks, etc.
Other dice are used for damage rolls, hit dice, and other uses.
In general, a high roll is more benefitial than a lower roll, e.g., better chance to hit or save, more damage, etc.
Automatic hits and misses[]
An automatic hit is an attack that hits regardless of target AC. Automatic hits occur on an attack roll of natural 20 or as a result of certain spells. A natural 20 attack roll is also a threat -- a possible critical hit.
An automatic miss is an attack that misses regardless of target AC. Automatic misses occur on an attack roll of natural 1.
Die Roll & Damage[]
Certain damage in NWN2 is based on dice rolls such as a weapon attack or sneak attack. Some of the damage done through die rolls can be increased if a critical hit is landed while some dice rolls aren't. Having a lot of die rolls doesn't guarantee more damage. The more die rolls you have means you are capable of doing burst damage. Think of having multiple die roll on a attack as trying to hit lottery. For example, a Barbarian 29/Fighter 1 build using a Bastard sword who has both Overhwhelming Critical and Thundering Rage feats will have three die rolls when landing a critical hit. First, the Bastard sword damage is calculated, which will be 2d10 on a critical for 2 to 20. Secondly, the Overwhelming critical of a 1d6 for 1 to 6 damage. Finally, Thundering Rage will add 1d8 for 1 to 8. The outcome will be 4 to 34 + Strength bonus. Depending on your strength score/bonus, your strength will be doing the majority of damage based on the number of times you swing.