These men come from various noble families in order to fight for their kingdom and do so in order to uphold their family traditions and maintain the reputation that their family has created and held for many generations. Their nobility provides them with funds for extensive combat training and top quality armour.
Treat these units like recruits; they need to be upgraded as soon as possible as in their current state even bandits and brigands are a serious threat for them. In battles, move them far away from the actual fighting, they always come mounted so speed is one advantage for them. These men are not to be underestimated as they have the potential to upgrade into several powerful units.
To access Pendor Noblemen you need to have your own kingdom and have chosen the culture to be Pendor. You can then recruit them from any castle/town that you personally own, as long as they have a training ground.