The Arrows of Light are an elven supremacist organization dedicated to defending and advancing the interests of pureblood elves, and expunging all traces of "impurity" from the elven species. Their veneer of culture and civility masks a ruthless fascist ideology that sees all non-elves as either animals to be used or threats to be neutralized, and their fast, stealthy raider ships are supported by secretive patrons in high places amongst the civilized worlds.
The Arrows of Light hold that elves are the perfect beings. Naturally blessed with near-immortality, high levels of culture, and magical affinity, they believe that elves once lived an idyllic, utopian existence in their own "Sylvan Plane", but that curiosity about other races led to the erosion of both elven culture and bloodline purity and their eventual expulsion from the realm by the primordial elven gods. Only by physically and ideologically "purifying" the elven species can they gain re-admittance.
The Arrows seek to preserve and glorify things that they deem to be purely elven, and put vast amounts of effort into archeological expeditions into elven ruins, and building museums of elven culture. Conversely, they seek to destroy relics and practices they identify as perversions, such as histories showing peaceful cohabitation with other species, or artwork showing influence by non-elven sytles.
This puritanism takes an even darker bend when it comes to creatures with elven blood. Arrow of Light doctrine holds that any partial elf is an abomination that must be destroyed, and its agents pursue this goal with assassination and targeted killings within lawful society, and outright mass butchery in places where there's no force to oppose them. Even those who appear to be pure elves are suspected of taint, and the Arrows of Light practice an arcane eugenics program that aims to breed those whom they deem to be the purest exemplars of elven heritage in order to elevate their ideals. While this has created a few scions of terrible beauty and tremendous power who lead the Arrows' raiding fleets, it has also created many twisted and degenerate monstrosities. Unfortunately for their victims, the order is all too willing to put these offspring to work as frontline soldiers.