Glowbeam
A Glowbeam is a stream of Celestial Aura connected at two points, generated from the focus point of a Luminous creature. It loses accuracy the further from its generation point it travels.
Effect
Glowbeams deliver a powerful, focused payload of Aura from a distance. It is primarily used as an attack. It is the most powerful way to move Aura from one place to another.
The affect of the Glowbeam depends on its intensity and its Luminosity. Solar Glowbeams cause burns and start fires. Lunar Glowbeams cause frostburn, frostbite, and freeze nearby water.
Side/Secondary Effects
The Glow cost of casting a Glowbeam is high. Any other processes--including passive or automatic ones--that use Glow will be weakened or disabled when a Glowbeam is charged and cast. Dragon wings are particularly hard to sustain while casting a Glowbeam.
Manifestation
Glowbeams look like lightning bolts that do not branch off. Their brightness depends on their power level, and their color depends on the Luminosity of the caster.
They are most straight nearest to their generation point and become more and more erratic the further they get from that point.
Source
Casting a Glowbeam requires a robust celestial core and nexus system and a large store of Glow. It is rare that more than two strong Glowbeams can be fired in succession without having to recharge.
How much Glow is used to cast the beam will determine how far it can travel. Though Glowbeams can travel as far as 50 meters, they do not travel in a straight line and lose accuracy the further from their source they go.
Glowbeams must be cast from a focus point. Attempting to cast more than one beam from different focus points at the same time causes a lot of strain on the nexus, leading to high risk of Bloodburn or Combustion.
I guess for most things the glowbeam is a last resort, as it drains so much.
Correct! Or sometimes it's a trump card that ends conflicts before they start ;)