Wandering knight

"The only thing separating a wandering knight from an ordinary mercenary is their vow."

In the end, to a peasant in the prefiphery it might be difficult to tell a wandering knight apart from a normal sellsword or a mercenary, as all do offer their services for a price. Rarely, though the wandering knights might do things for free, for their own reasons or of the loyalty towards their liege.
A wandering knights is a soldier, who was given their knightly vow to serve their master or a knightly organisation, brotherhood or similar, but has taken upon them to better the world and help people like they see fit, wandering around the country or even the whole continent and further, where ever their steps lead them. They are lone wolves, but it doesn't mean they would all be grumpy and antisocial. Some might form small bands from time to time, help adventurers or even join an adventuring party for whatever is driving them. Some wandering knight might be holy knights i.e. paladins, but nearly not all.
Wandering knights are often met with curiosity and mild wariness, but usually the attitudes of the people towards the knights are neutral or positive, as the knights often help rural communities with their problems much better than the ordinary military forces who rarely have time or interest on the periphery's problems.

Career

Qualifications

A vow separates a wandering knight from ordinary mercenary or sellsword. The knights usually follow some kind of chivalric code, whatever it might be. One also needs to have some weapon training, as knights usually do.

Career Progression

Some wandering knights might gather quite a reputation, sometimes even big enough that they are called to active service in the military force or in their order. Some accept this 'promotion' eagerly, but the others would rather continue their independent way of wandering around and helping people in need. The latter is true especially when it comes to the those, who have chosen their path due to religion.

Type

Military