The Moonlight Order (or The Order of Elore'alah) is a religion founded hundreds of years ago by Count Lucien Von Sanguinar on the island of Talonpeak. It has since been followed by the inhabitants and his descendants. It is currently lead by Kezia Sanguinar and her husband Dantias Elden Sanguinar.
What "You" Might Know
The Moonlight Order is a cult supposedly of a bat-themed god known as Ac'dural (also known as the "Holy Bat" and "The Nocturnal Light"). Through their god they have learned Lunar Magic as well as Life Magic. To them, Ac'dural is the personification of The White Lady. Making them some of only a few humans who worship the moon like the Kaldorei.
What You Likely Don't Know
(SPOILERS from this point forward)
The Moonlight Order follows the Doctrine of Ac'dural, which states that the use of the Nocturnal Light (Lunar Magic, or Silver Light) comes from their belief in Ac'dural and by extension the moon itself. The contradictory nature of the personification of The White Lady is not lost on them, however. They are aware that the form that she has taken being male is odd and while their scholars discuss it, they never stray too far from their belief in him.
Additionally, they utilize life Nature Magic as Life Magic, similar to the Kaldorei in a few ways save one. They practice Hemomancy (blood magic), and while there is debate on its practice among newcomers, it is widely accepted among them that blood magic is not a perversion of life, but an extension of it.
While they believe in the Light and practice the arcane, they believe that the Nocturnal Light is the Light in its most pure form. They believe that the Night Elves are their closest relatives in terms of religious practice and belief of the moon, however believe that they are on the correct path while the Night Elves have stagnated themselves in their ridged belief in inherent darkness. With this mindset, the followers of the Moonlight Order are able to justify most any use of their otherwise forbidden knowledge. They even practiced necromancy, though not to the degree that others may. They believed that their use was an application of Life Magic and thus not evil.
Due to the fall of House Sanguinar, practice of the Moonlight Order became more secretive and after the Scourge ravaged Lordaeron they had taken a different mindset to necromancy as a practice, not viewing it as evil, but knowing that it could be abused. They banned the use of necromancy in their order and it was long gone by the point that Kezia Sanguinar took back her home and resumed religious practice.
The Crimson Harvest
Once per year, between 2 to 4am on Hallow's End the members of The Moonlight Order draw blood from one another into a bowl before saying a prayer. Once said, the members drink the blood of their fellows. This ritual however is different for the Talonguard who take a sip of the blood of the head of the house. Similarly the head of the house must drink the blood of a virgin. Once complete they spend the rest of the day partying until 11:59pm when they make a final prayer to Ac'dural and depart for bed. It is believed that after this festival that those who partook in the blood gain a blessing from Ac'dural. Blood donations and access blood go into the Bloodwell, a well constructed to slowly deliver the blood directly to Ac'dural.
Note: This was how Lucien Von Sanguinar and the High Elves who followed him maintained themselves in place of the Sunwell and what changed them into more vampiric appearing elves.
After hundreds of years of worship and their elven heritage the Sanguinars are all born with silver eyes, enlarged canines and likely blood red hair. Though, followers of the Moonlight Order can develop them on their own over time and devotion. However, something very interesting happens when a Sanguinar uses blood magic, the whites of their eyes shift colour to a bloody red.
An interesting exception to the usual traits Sanguinars are born with, Lucien Sanguinar (Kezia's son) was
born not only with silver eyes, but also pointed ears despite his father being human. While it was debated on whether Kezia was unfaithful or it was a gift from Ac'dural it was accepted that Kezia's son was in fact the reincarnation of Lucien Von Sanguinar, the religions founder and thus he has become a messiah in the eyes of their followers, to the dismay of some of his family.