Dunno about Ley Lines, but the Mist does have a source. Still, story for another time.

[He shakes his head at her question.]

Nah. You have to be in the Mist for a long time, and every kingdom had pretty much learned to build themselves above it and shut it out completely. If you have to travel long distances, we have airships to fly above it.

[He's not... gonna talk about what Mist exactly is.]