Attack Rolls And Critical Hits
The attack roll is made with a d20. The attacker adds his character class attack bonus and the opponent’s AC to the roll, as well as any other situational modifiers. After adding all bonuses to the die roll, a result of 20 or greater is a hit.
Natural 1: Fumble
A natural 1 (when the die itself shows a 1) is a fumble. This means an automatic miss, that the character drops their weapon, and that the weapon might be broken. Roll 1d8 to see where the weapon is dropped. 1-6 indicate the hexes clockwise around the character, starting with the hex the character is facing; 7-8 indicate the character’s hex. If the indicated hex is impenetrable for some reason, the weapon just lands in the character’s hex. Then, roll 1d6. On a 1, the weapon is broken.
A natural 2 is normal with a melee weapon, but can signify friendly fire if the attacker is using a ranged weapon.
Natural 20: Critical Hit
A natural 20 is a critical hit. Damage is rolled normally, with all modifiers, and the result is doubled (2x).
Some criticals do even greater damage on the critical hit. Roll an additional d20; if this is also a natural 20, then the attack is does 3x damage instead of 2x. In this case another d20 is rolled to see if it is a natural 20 and therefore actually a 4x crit, and so on. This rule continues indefinitely. If a natural 19 is rolled and the target does not have a helmet or equivalent natural protection, the damage is still increased as if a 20 was rolled, but the attacker doesn’t roll another d20.
If a character requires a natural 20 on the die just to hit some creature, then the character’s 20s will not count as critical hits.