The Concordant Knights are a defunct order of angelic peacekeepers. According to Payapop Pritrum in the 5th Treatise on Aeons, the order was established with the purpose of protecting reality. It is implied most, if not all angels were allied with the Concordant Knights, but when the Universal War broke out, the order was functionally dissolved.
82 White Chain Born in Emptiness Returns to Subdue Evil still considers themselves to be a Concordant Knight.
"The comb of Prim, the symbol of our oath. Do you recall it's meaning ? ... The Oath is to preserve and glorify the works of God, not to covet or control them ! To defend the weak and powerless, not terrify them ! It represents gentleness, White Chain." King of Swords 9-121
The Concordant Knights were founded some time before the Universal War, likely during the angelic reestablishment in Throne. For many years they maintained peace throughout the multiverse, handing down martial arts dating back thousands of years and teaching the ways of law enforcement. Through the process of reincarnation, it appeared the angels would always remain loyal to the order.
However the Concordant Knights were unable to survive the Universal War and became splintered by violent upheaval. The Shattering killed an inestimable number of warrior monks, leaving a generation of young angels without leadership. Upon witnessing this destruction, most of the survivors became disillusioned with their ability to enforce the law. Some became independent and chose to sell their services as mercenaries, while others gathered to form the order of Thorn Knights. Those who remained continued their peacekeeping duties by establishing the Concordant Harmonies.
He who drinks oceans of blood shall never cease bleeding from the mouth.
“Once, there was an angel with a flaming spear that guarded the western gate of YISUN’s speaking house. He was rigorous, martial, and followed the exact letter of the Old Law that had been inlaid into his very being with Koss’ silver chisel. At the time, most angels were like him, and they were exceptionally inflexible beings. They could not rebel, so well they had been hewn, against the slightest violation of their code. This made them all extremely cruel.
One day, Prim passed by on the road, and happened upon this angel flogging a group of men of the oldest nation with a lash made of lightning. The men had refused to take their shoes off inside of YISUN’s speaking house – they had journeyed far and did not know the law of the gods. For this minor offense they were being punished rather severely, and their cries were loud and fierce.
Cleverly, Prim took her jeweled comb from her pocket, which she no longer used, since she had long ago hewn off most of her beautiful hair, and bade the angel guard it with his life. Being a lesser being with no practical free will to speak of, the angel could do naught but comply.
Turning back to his prisoners, the angel made to flog them again, but found that the comb was so delicate that every violent motion he made sent it tumbling and ringing and threatened to shatter it. He could no longer continue his violent, oppressive work without fear of harming his duty to the daughter of Hansa, to protect this small and delicate thing.
He gave up flogging the men, and for the first time ever, began to think.”
“It is often speculated upon why Concordant Knights start their pre-combat prayer for forgiveness of violence with an attempt to propitiate Aesma, by far the most violent, rampant, and willful of the gods. The answer, as I was told by one particularly old angel who held watch over a decaying section of the King’s Road, is extremely simple: if anything was horrendous enough to offend Aesma, it was enough to offend all the other multitudes of gods, thus the prayer is started by opening the largest flood gate of them all, so to speak.”