Luck is a combat variable, that may cause a creature stack to do additional damage. As can be seen from the table on the right, there are three levels in luck modifier: positive (+1), good (+2) and excellent (+3). Luck can also be neutral (zero), which means that a creature stack can not get a "lucky strike". Creature stack's luck modifier depends mainly on hero's luck status, but can also be affected by spells (Fortune, Misfortune) or creature abilities (e.g. Devils). Additionally, Shadow of Death expansion introduced magical terrains that can affect luck modifiers. Hero's luck depends on equipped artifacts, possible luck secondary skill and/or visited Adventure Map locations.
There are several references in the game, that receiving luck during combat causes double damage. However, this is not entirely accurate because the damage is not simply multiplied by two when lucky strike appears. Receiving luck when attacking means that the creature stack does additional base damage on top of the regular damage. This additional "lucky damage" is not affected by the differences in the attack and defense skills, but is affected by other variants such as obstacle penalty. Thus, the final damage is not actually doubled.
Luck affecting features
Adventure Map locations:
- Faerie Ring increases luck +1 until next battle
- Fountain of Fortune gives random amount of luck from -1 to +3 until next battle
- Idol of Fortune increases luck +1 until next battle on odd days (+1 to morale on even days, and on day seven gives both luck and morale +1)
- Mermaids increases luck +1 until next battle
- Rally Flag increases luck +1 (and morale +1) until next battle
- Swan Pond increases luck +2 until next battle (also causes hero to lose all remaining movement points for the day)
- Events may increase or decrease luck from -3 to +3.
- Clover field increases luck neutrally aligned creatures by +2
- Cursed Ground entirely disables luck effects.
- Cards of Prophecy increases luck +1
- Clover of Fortune increases luck +1
- Ladybird of Luck increases luck +1
- Still Eye of the Dragon increases luck +1 (gives also +1 to morale)
- Pendant of Courage increases luck +3 (gives also +3 to morale)
- Hourglass of the Evil Hour negates all luck
- Rampart's Fountain of Fortune increases luck of defending hero by +2 when defending against siege.
- Rampart's grail building Spirit Guardian increases owners all heroes' luck by +2.
- Devil decreases enemy luck by -1
- Arch Devil decreases enemy luck by -1
- Halfling always has luck value at least +1
- Luck secondary skill increases luck by +1, +2 or +3.
- Fortune increases luck by +1 or +2 (or +3, if the hero has a specialty in fortune)
- Misfortune decreases luck by -1 or -2.
It has been asked in several forums whether luck can be negative and whether a creature stack can receive "bad luck". The answer is no. Luck can only be neutral (0), positive (+1), good (+2) or excellent (+3). In the first release of Heroes of Might and Magic III: Restoration of Erathia, there are few references within the game that the luck could be negative and cause a troop to do halved damage. There is even a sound reserved for the bad luck effect that can be found within the game files. The best guess is that the game developers have planned to include bad luck effect, but for some reason have left it out in the released version, however; in some fan-based modified versions of the game, this feature has been enabled.