Ley Lines

[Nnystyxx]

I don't really like the whole ghost thing, something more mystical and less "another way to metagame" would be better.

Whatever their function is, mesons and thermals should be able to see them. There could also be some sort of dowsing rod to help detect them.

Wizards could also maybe see them, and use them to empower spells or something.

could also possibly tie in with a way to damage or empower wraiths depending on the circumstances, they appear & connect random departments giving these roles a reason to go places in particular rather than wander around murdering aimlessly