Attack Roll
The attacker makes an attack roll. The defender makes a defense roll. These are compared. If the attack roll (with modifiers) is greater than the defense roll, it hits. If not, it misses. The attack and defense rolls are modified by a random number (which is added) and a fatigue penalty (which is subtracted).
Attack Roll
Attack roll: Weapon's Attack value
+ Attack modifiers, if any
+ DRN
Defense roll: Defender's Defense value
+ defense modifiers, if any
+ DRN
Defender wins ties!
Once a hit is scored, a similar calculation is done to determine how much damage is done. This involves the attacker's damage roll minus the defender's protection roll.
If the defender has a shield, the hit is a shield hit unless the attack roll beats the combined value of the target's defense and the shield's Parry value plus the random roll. If a hit is scored as a shield hit, the shield's Protection value is added to the defender's Protection roll.
Example: Vanjarl vs Heavy Infantry
- A Vanjarl is attacking a Heavy Infantry unit. Neither unit has any fatigue yet.
- The Vanjarl has an attack value of 14.
- The Heavy Infantry unit has a broad sword, chain mail hauberk, half helmet and shield. It has a base defense of 10, gets a defense bonus of +1 from the sword, a defense penalty of -2 from the armor, and a defense penalty from the shield of -1. The shield's Parry value is 4. The actual defense is 10 +1 -2 -1 = 8. With the shield's Parry value, the unit's total defense is 12.
- The Vanjarl rolls a 6, for a total attack value of 20.
- If the Heavy Infantry rolls a 7 or less, it is a clean hit and the shield offers no protection. If the Heavy Infantry rolls an 8 through 11, the Vanjarl scores a shield hit and the Heavy Infantry can use its shield's protection value in the damage calculation. If the Heavy Infantry rolls a 12 or higher, the Vanjarl misses entirely.
Attack modifiers
Both attack and defense can be affected both positively and negatively by various effects. Due to the complexity of the game it will be difficult to list all of them, but here are some of the more common ones.
Positive Attack modifiers
| Equipment | Weapon bonus | Only applies to attacks with that weapon |
| Magic Item bonus | Applies to all attacks • E.g. Burning Pearl • Ring of the Warrior | |
| Bless | When blessed |  3 Attack: +2 attack •  10 Quickness: +2 attack •  4 Berserker: +2 attack when active •  4 Blood Surge: +3 attack when active • Throne effects |
| Unit attributes | Experience | +1 attack per  |
| Berserk | + Berserk value to attack when berserk | |
| Dark Power / Storm Power | + value in Darkness / Storm | |
| Chaos / Magic / Death / Cold / Fire Power | + value / scale | |
| Spells | Quicken Self • Quickness • Quickening | +2 attack |
Negative Attack modifiers
| Equipment | Weapon penalty | Only applies to attacks with that weapon |
| Multiple Weapons | Penalty = Combined Weapon Length • Reduced by Ambidextrous value | |
| Unit attributes | Afflictions | Variable |
| Invisibility | -10 attack • Negated by Spirit Sight | |
| Chaos / Magic / Death / Cold / Fire Power | - value / opposing scale | |
| In combat | Fatigue | -1 / 20 points of fatigue • At 100 fatigue the unit can no longer attack |
| Frozen | -3 to attack | |
| Slime | -2 to attack | |
| Terrain | Caves and Deep Sea | -3 attack • -2 with 50% Darkvision • No penalty with 100% Darkvision, Spirit Sight or Blind Fighter • Solar Eclipse mimics this effect |
| Swamps | -1 to attack • No penalty with Swamp Survival • Quagmire mimics this effect | |
| Underwater | Blunt and Slashing attacks have weapon length in penalty • Flails get an extra -1 penalty | |
| -3 attack when fighting underwater • -2 attack with Poor Amphibian • No penalty with Amphibious or Aquatic | ||
| Spells | Darkness • Utterdark | -6 attack • -3 with 50% Darkvision • No penalty with 100% Darkvision, Spirit Sight or Blind Fighter |
Defense modifiers
Positive Defense modifiers
| Equipment | Weapon bonus | Added to Defense value |
| Magic Item bonus | Added to Defense value • E.g. Cat Charm | |
| Shield Parry | Gives a Parry bonus | |
| Bless | When blessed |  3 Swiftness: +1 defense • 3 Defense: +2 defense • 10 Quickness: +2 defense • 4 Blood Surge: +1 defense when active • Throne effects |
| Unit attributes | Experience | +1 defense per |
| Dark Power / Storm Power | + value in Darkness / Storm | |
| Chaos / Magic / Death / Cold / Fire Power | + value / scale | |
| Spells | Quicken Self • Quickness • Quickening | +2 defense |
| Water Shield • Water Ward | +5 defense • Only underwater |
Negative Defense modifiers
| Equipment | Weapon / Armor / Shield penalty | Variable |
| Bless |  43 Larger | -1 defense (always active) |
| Unit attributes | Afflictions | Variable |
| Berserk | - Berserk value to defense when berserk | |
| Chaos / Magic / Death / Cold / Fire Power | - value / opposing scale | |
| In combat | Fatigue | -1 / 10 points of fatigue • At 100 fatigue defense is set to 0 |
| Harassment | -1 / enemy attacks • halved if mounted • Mitigated by Unsurroundable | |
| Frozen | -3 to defense | |
| Slime | -2 to defense | |
| Defense reduced by 75% | Webbed • Earth Grip • False Fetters • Netted • Entangled • Stunned | |
| Defense set to 0 | Petrified • Paralyzed • Sleeping • Encased in Ice | |
| Terrain | Caves and Deep Sea | -3 defense • -2 with 50% Darkvision • No penalty with 100% Darkvision, Spirit Sight or Blind Fighter • Solar Eclipse creates the same effect |
| Swamps | -1 defense • No penalty with Swamp Survival • Quagmire creates the same effect | |
| Underwater | -3 defense when fighting underwater • -2 defense with Poor Amphibian • No penalty with Amphibious or Aquatic | |
| Spells | Darkness • Utterdark | -6 defense • -3 with 50% Darkvision • No penalty with 100% Darkvision, Spirit Sight or Blind Fighter |