Damage increases with consecutive attacks, as long as attacking persists and is not interrupted.
Carthus Beacon synergizes very well with the Pontiff's Right Eye, which in turn, further amplifies the damage of the caster's attack chain. This works well for players with aggressive playstyles, allowing them to chain their light attacks to quick rack up damage on a target.
It does not last very long, and requires two attunement slots and a sizable amount of FP to be used. It should be cast like one would cast Power Within, when there is ample time and space to do so, and not in the heat of combat, as being staggered will prevent it from being cast.