The Order of the Moonlight Horse (月光木馬團) was an assassination organisation that had been operational since the Dark Ages, until its destruction in S. 1197. The Dark Ages ended in S. 500, meaning the organization had existed for at least 700 years.
The Order of the Moonlight Horse was an organization of assassins. Sharon Kreuger was formerly a member; back then, she had the title of "Severing Chains" passed down to her, and she was only known by her designation as "Kreuger" (not taking up the name "Sharon" until much later). She described herself as being its second most skilled member when she was 13 (in S. 1194).
In its final years, the organization held a rivalry with a then-new faction, Ouroboros, behind the scenes. In S. 1197, the rivalry ended when Ouroboros's most powerful agents - McBurn, Leonhardt and Arianrhod - destroyed the Order. However, three of its members migrated to Ouroboros: