Generals are the promoted versions of Knights. They have excellent defense, good attack, surprising evasive ability for their size and bad resistance. They are quite slow, but what they lack in maneuverability they make for with defensive and offensive ability.
Generals can be used like "walls" to block enemy forces and are quite useful in survival and defense objective battles. They can be used to block small entrances to prevent opposing units from getting past them, this is very useful if you wish to stop thieves from escaping. A General's weaknesses are magic and anti-armor weapons, as well as fast moving durable and powerful characters like Heroes, experienced Paladins and Warriors. The rarity of a general ever being out matched on the field through sheer brute force is high, which means they are very valuable to any team and their durability is very helpful to weaker units as they can hide behind them.
The first knight that joins, Travis, joins in Chapter 2. Cook joins in chapter 9. Both require additional experience to become a General. However, Elaine starts as a General, but does not gain experience. In the Prologue, Matthew is also a General.