Increases the damage dealt by the hero's ranged units (+10% / +25% / +50%) and removes the through-wall penalty during sieges.
During a siege, increases the catapult's number of shots, damage and accuracy (1 shot / 2 shots / 2 shots with a guaranteed wall breach).
Lowers the threshold for neutral creatures to offer to join the hero (to 8 / 6 / 4) and increases how many join (25% / 50% / 100%); it also reduces the surrender cost to 40% / 30% / 20% of army value (50% without the skill).
Gives a chance to learn a spell cast by the enemy (20% up to level 2 / 30% up to level 3 / 40% up to level 4).
Increases the morale of the hero's troops (+1 / +2 / +3). Not available to Necromancers.
Increases the natural (1/day) rate of spell-point regeneration (to 2 / 3 / 4 points per day).
After a victory, raises a portion of the slain enemies as Skeletons that join the hero's army (10% / 20% / 30%).
Reduces the movement penalty for crossing rough terrain on the adventure map (the amount depends on the terrain type).
Increases the hero's view radius on the adventure map (+1 / +2 / +3 tiles).
Allows the hero to learn spells of level 3 and higher (level 3 / level 4 / level 5).