Primary skill
Primary skills are characteristics of heroes and creatures. There are four different primary skills: attack, defense, spell power and knowledge. Attack and defense can be categorized as might skills while power and knowledge are magic skills. Typically might heroes, like knights and rangers, advance more rapidly in might skills as for magic heroes, like necromancers and wizards, advance faster in magic skills. The advancement in primary skills vary considerably by the hero class on levels 1 to 9, but afeter that, hero's advancement generally becomes more balanced.
Attack skill
Attack skill together with defense are the main main factors affecting the amount of damage creatures under hero's command deals. A hero's attack skill number is added to each of their creaturess attack rating, increasing the amount of damage they do in combat.
Spells altering attack skill
Mana spent skilled is the spent mana cost being reduced because of specialisation in the magic variant and thus having Earth Magic, Fire Magic, Water Magic or Air Magic (whatever school the spell is in, some first level or second level ones are universal and belong to more than one school) as a secondary skill (no matter if on basic, advanced or expert).
| Spell | Spell Level | Mana spent | Mana spent skilled | Change | AttackBuff | AttackBuffAtAdvanced | AttackBuffAtExpert |
|---|---|---|---|---|---|---|---|
| Bloodlust | 1 | -5 | -4 | Attack (Own) | +3 | +6 | all own units |
| Weakness | 2 | -8 | -6 | Attack (Enemy) | -3 | -6 | all enemy units |
| Frenzy | 4 | -16 | -12 | Loose all Defense, gain some Attack | Defense lost = Attack gained | Attack gains 150% former Defense, Defense is lost | Attack gains 200% former Defense, Defense is lost |
| Precision | 2 | -8 | -6 | Ranged attack (own) | +3 | +6 | all own ranged units |
| Slayer | 4 | -16 | -12 | Attack (own) against Level 7 Creatures | +8 against Dragons, Hydras, Behemoths | +8 against Angels, Devils | +8 against Titans |
| Prayer | 4 | -16 | -12 | Speed, Attack, Defense increased | Speed, Attack, Defense increase by +2 | Speed, Attack, Defense increase by +4 | all own units |
Defense skill
Defense skill together with attack are the main main factors affecting the amount of damage creatures under hero's command deals. A hero's defense skill is added to each of their army creature's defense rating, which decreases the amount of damage they take from enemy attacks.
It should be noted, that while defence is acceptable spelling, it is always spelled defense in Heroes of Might and Magic III (with the exception of Heroes Chronicles, where it is spelled defence).
Spells altering defense
| Spell | Spell Level | Mana spent | Mana spent skilled | Change | DefenseBuff | DefenseBuffAtAdvanced | DefenseBuffAtExpert |
|---|---|---|---|---|---|---|---|
| Frenzy | 4 | -16 | -12 | Loose all Defense, gain some Attack | Defense set to 0, Attack gained is former Defense | Defense set to 0, Attack gains 150% former Defense | Defense set to 0, Attack gains 200% former Defense |
| Prayer | 4 | -16 | -12 | Speed, Attack, Defense increased | Speed, Attack, Defense increase by +2 | Speed, Attack, Defense increase by +4 | all own units |
| Shield | 1 | -5 | -4 | Reduction of melee damage (not ranged one) | -15 % damage taken by melee damage | -30 % damage taken by melee damage | all own units |
| Stone Skin | 1 | -5 | -4 | Defense rating increase | +3 | +6 | all own units |
| Air Shield | 3 | -12 | -9 | Reduction of ranged damage (not melee one) | -25% damage taken by ranged attacks | -50% damage taken by ranged attacks | all own units |
Frenzy and Prayer from the "attack modifying spells" were mentioned before so they are the first spells to be mentioned in defense modifying spells here.
Stone Skin is worse than Shield. Air Shield is bugged and increases the damage from Arrow Towers. The Spells stack and can be used in paralell (only 3 effected spells are displayed - maybe using a 4th spell overrides spells stored so far).
Power skill
Power (or sometimes spell power) is the main factor for damage and duration of the spells. By default, all heroes start with at least one point in this skill. However, a map-maker can set the starting skill to 0. In that case, the hero will look and function as if he had power of one point. When the hero recieves the first point to power skill, he will still have only one point in power. After that, the points accumulate normally.
Knowledge skill
The knowledge skill determines the maximum amount of spell points a hero may have. It is calculated by multiplying knowledge with ten, so knowledge of 13 would give a hero a natural maximum of 130 spell points. With the secondary skill intelligence, this natural maximum can be increased up to a 100%, which will double the hero's maximum spell points. Additionally, with mana vortex or magic spring hero can temporarily double the spell points, which means that with expert intelligence, the maximum spell points will be quadrupled from original amount.
Like with power, all heroes typically start with at least one point in this skill. However, a mapmaker may set the starting skill to 0. In that case, the hero will look and function as if he had 1 point, but when he receives his first point, it will not have any effect.