Leylines are natural channels through which magical energies of the world tend to travel, akin to how water passes down rivers. Leylines can have a variety of effects, and can be potentially be tapped into to enhance or modify spells or cast otherwise impossibly large rituals. While they are unseeable to the naked eye, they can be discovered through the detection of magic, or if it is a powerful leyline, through observing its effects on the environment. While some claim to have comprehensive maps of the most important leylines, discovering, confirming, mapping and experimenting on leylines remains an active process in many corners of the world. It’s a popular truism that Leylines are a microcosm of the flow of essence that characterises the Great Flow.
A researchers work mapping out leylines. (Wikimedia Commons - Alfred Watkins’ map).
Philosophia is famously founded on leylines and their use. The Pactlaw of the city is a sort of set of rules the city’s founders engineered the leylines to magically enforce. The megacity is still a centre of interest in and research of leylines.
Since the Great Silence, some Crusader Sects following Utopian Theory have attempted to understand and use leylines to reach Utiopia, the plane the Titans are speculated to have gone to.
In more recent history, many researchers claim the Leylines have behaved eratically, shifted courses, and sometimes even appeared and disappeared. This has been dubbed the Leyline Problem.
During his time researching leylines in Horiza, Magnus Strike was on multiple occasions attacked by a set of Leyline Creatures after attempting to tap into the local leylines of Friedport. He would also uncover a leyline map of Friedport in a ruin on the island of Bigthraun, presumably left behind by Horizan Precursors. During the culmination of the Landcrab Plot it is believed these leylines were used to empower the large swathes of golems unleashed on the city of Friedport, as well as on the barrier put around the city to contain said threat by the Magus in the High Tower.
While leylines are not largely present in Vilhun lore, there appears to be a large quantity of divine leyline roots stemming from the central Flod mountain, where the One & Only and her Hun Lords shrines reside.