Charisma is a attribute that influence your ability to lead troops and build cheaper. for each Trade skill you have to pay % less resources to build buildings, research or train troops, Trade skill increases with a falling function. If you have less that 5 charisma you have to pay additional resources.
For each Charisma Point you get
- +1 Trade skill
For each 2nd Point you get
- 1 Morale
For each 4nd Point you get
- +1 following Unit (Up to 8 at 28 Charisma)
- +1 Influence radius (but sadly it doesn't increase at higher level)