Leyline

A leyline is a conduit through which magical energy flows. Where leylines intersect, a nexus may be formed.
Rune magic operates by manipulating the flow of leylines, or even rupturing them and channeling their full energy flow into a spell. The use of rune magic during the Rune Wars caused considerable damage to Runeterra's arcanosphere, and the resulting thaumatoxicity destroyed nearly all of Runeterra's indigenous elementals and other magic-based entities.Tides.
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