fak
Regular

In the current version you can't really join a force (doesn't mean joining the factions while the lords don't assign you to a group.) but end up being the leader. I hope in further versions we can join forces ,e.g. being a member of a warparty, or join the manhunters to hunt slaves. In those situations computer takes the leading role. Slowly, with decent leading skills and high ranks (or big bucks), you will be assigned a group of soldiers under your command by the king (or start being a mercenary leader and build your force).
Of course you can be a leader at the very beginning of the game, if you already have leading skills and denars.
Of course you can be a leader at the very beginning of the game, if you already have leading skills and denars.