Rafiki wrote:To start with the last; there are some generals that will increase the number of conscripts a city will generate (I can't recall which special ability it is they need to possess right now), but generals have no effect on unit creation; they will either arrive by event or by you recruiting them through the recruitment screen.
Welcome put -
The ability is Recruiting Officer, symbolized by a black pennant on a gold background. The general has to be inside a large city to use it. I think level 5 or up. Most generals who have the ability are poor field commanders, so this is the best way to use them.
Patriot special ability uses the same symbol, it increases the chances for partisans and volunteers in the same state as the general. The general doesn't have to be in a city. (Not sure exactly how the mechanics of that one work, and not sure if I've ever seen any benefits from it.) Most generals with this ability are decent field commanders.
There are some abilities ... Artillerist, Entrencher, Seige Expert, Training Officer, etc. that belong in large stacks whether the general is given troops to command or not.