Charm in Heroes 4

A hero with Basic Charm can convert 15% of greatly outnumbered hostile creatures to his side. The hero can convert no more than 60 experience points of creatures, plus 10% per level of the hero. The cost of surrendering is 90% of normal.

Advanced Charm allows the hero to convert 20% of greatly outnumbered hostile creatures to his side. The hero can convert no more than 120 experience points of creatures, plus 10% per level of the hero. The cost of surrendering is 80% of normal.

Expert Charm allows the hero to convert 25% of greatly outnumbered hostile creatures to his side. The hero can convert no more than 180 experience points of creatures, plus 10% per level of the hero. The cost of surrendering is 75% of normal.

Master Charm allows the hero to convert 30% of greatly outnumbered hostile creatures to his side. The hero can convert no more than 240 experience points of creatures, plus 10% per level of the hero. The cost of surrendering is 70% of normal.

Grandmaster Charm allows the hero to convert 35% of greatly outnumbered hostile creatures to his side. The hero can convert no more than 300 experience points of creatures, plus 10% per level of the hero. The cost of surrendering is 65% of normal.