Ley lines are channels of magical energy that criss-cross the land - many people in the real world believe they exist, so it's reasonable to suppose that you can find them in worlds where magic is real! Here, they are accessible to casters of both arcane and divine magic. Details of where they are to be found (along with a note on their presence in the Midgard Campaign Setting) and how they are detected are accompanied by notes on how they are actually used - basically, a caster taps into ley line energy to provide a burst of power to the spell he is casting at the time. The effects can be a bit unpredictable, but a caster can 'lock' a particular ley line to get rather more consistent results.
If you do use the Midgard Campaign Setting there's a map showing where the ley lines are. If you don't use it, the map will serve as an example of how to distribute them across the surface of your chosen campaign world.
Tapping in to a ley line requires specialist knowledge, provided by taking the appropriate feat (or by studying with a geomancer during downtime), and a die roll to measure the level (if any) of success. Random effects can be obtained even from a 'locked' ley line if the roll to tap the line is not very good. Several tables, based on how powerful the ley line is, are provided to supply the random effects... and if the roll is really bad the caster can suffer backlash effects!
There are two feats to choose from, as well as the geomancer arcane tradition for those who want to immerse themselves in the study of ley line magic. Unlike many traditions, it is not a specialisation of itself, but intensive study of how to use ley lines irrespective of what sort of magic is being cast. Some practitioners of magic rather look down on geomancers due to the nature of their studies - but I can see how it's a potentially useful discipline, especially as they appear to be the only people with the ability to lock a ley line to themselves.
We then come to a collection of ley spells, which are available to druids, sorcerers, warlocks and wizards. Apparently despite the 'pure energy' nature of ley lines, other spell-casting classes do not have access to these spells - it's not clear whether or not they can access the ley lines themselves given the appropriate knowledge. Each spell has a full description and the necessary game mechanics to use it.
This is an interesting and nuanced exploration of ley line magic, which should make it straightforward to introduce it into your game.
Return to Deep Magic #5: Ley Lines page.
Reviewed: 19 October 2016