Fragments of info I've picked up on Pathmages:

* They have a guild
* They can conceal items that only another mage can reveal
* They can create wards to prevent sickness

Inference: They have a great interest in travel and exploration.

My Ideas:

Pathmages have three primary areas that they focus on, all of which use runes in some fasion: Warding, Dimensional Spaces, and Inscribing.

Warding involves applying runes to an object that oppose a specific thing. You could have a ward that blocks sickness, or a ward that turns aside cold. Wards however do nothing to protect the item the runes are applied to. So you could create ward stones to ward off lizard men (they would feel uneasy to sever pain, depending on strength) but the stones themselves would not be any stronger than normal stone, an easily shattered with a strong hammer. Wards take to wood and stone best, followed by cloth. The harder and more resistant to weathering and corrosion the metal, the harder it is to power the ward. The time take to apply the runes and the amount of power put into them determine how long the ward lasts and how strong it is.

Inscribing is similar yet different to warding. Inscribing is often called enchanting by laymen. With inscribing the pathmage carves and empowers the runes to release a specific magical effect with a specific trigger. So a pathmage could inscribe a stone with light runes with a keyword to activate it, and you have a portable light. The vast majority of inscribed items are one-time usage, so don't expect to see glow stones on every street corner.

Dimensional Spaces are a merchant's best friend, though the service comes at a steep cost. The pathmage inscribes a single rune to act as a key, then draws a complex sequence of runes in the air to open and close the space.