Primary skill

Primary skills are characteristics of heroes and creatures. There are four different primary skills: attack, defense, power and knowledge skill. Attack and defense can be categorized as might skills while power and knowledge are magic skills.

Attack skill

File:Hero attack.png

Attack skill together with defense is the one of the main factors affecting the amount of damage creatures under hero's command deals.

Spells altering attack skill

Mana spent skilled is the spent mana cost being reduced because of specialilsation 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

File:Hero defense.png

Defense skill together with attack is the one of the main factors affecting the amount of damage creatures under hero's command deals.

It should be noted, that while defence is acceptable spelling, it is always spelled defense in Heroes of Might and Magic III. However, it is spelled as defence in Heroes Chronicles.

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 lost = Attack gained	Attack gains 150% former Defense, Defense is lost	Attack gains 200% former Defense, Defense is lost
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).

Spell power skill

Spell power (also just 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 mapmaker might 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.

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.

However, with the secondary skill intelligence this maximum can be increased

by 25 % at basic (adding 1/4 of 10 per 1 skill point, 2.50 points additional so it becomes 12.50 points mana per point knowledge), 
by 50% at advanced (adding 1/2 of 10 per 1 skill point, 5 points additional so it is now 15 points mana per knowledge point) and
by 100% at expert level (being double the 10 points per skill point, making it 20 points per knowlege skill point).

This would mean, that with knowledge 13 and an expert level of intelligence, a hero would have maximum of 260 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 quadruple of the original.

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.