Tip
Charging up Arcanopulse [Q] leaves Xerath vulnerable to Lux’s Light Binding(Q) and Lucent Singularity(E), so try to use it while hidden inside a brush. Lux will try to use Final Spark (R) when Xerath uses Rite of the Arcane [R], so try to use the range to Xerath’s favor if Lux is running low on health.
Xerath vs Lux



