Intelligence
Intelligence is one of the secondary skills. It increases the hero's maximum amount of mana depending on the level of the skill. Normal maximum mana is ten times the knowledge skill, but at basic level of the intelligence skill it is increased by 25%, at advanced level by 50% and at expert level by 100%.
Heroes who specialize in Intelligence:
Discussion
Intelligence is a excellent supportive secondary skill. Especially in large and extra large maps, where heroes grow to be more "mighty and magical", the amount of mana points may become crucial. For example, resurrecting a large army can consume massive amount of mana points. Dungeon heroes may be able to pass Intelligence, because they typically have the opportunity to build Mana Vortex in their cities, which basically has the same effect as expert Intelligence – the spell point maximum is doubled.