By the time of the Third War, a faction had started growing in the Knights of the Silver Hand, largely led by Abbendis. This faction was intolerant of what they deemed as the "lesser races".“Deep beneath their monastery lies death. Death of a thousand rotting corpses who once were them but no more. Burned and soiled. That is where you go for a red prayer on moonless nights.”
High General Abbendis and his youthful charges were in the Capital City of Lordaeron, when it was attacked by the Scourge during the Third War. Priests and paladins fought as the Scourge attacked the city, but Abbendis fled with Isillien as Lordaeron fell around them. It is believed, that the wounds both men received in battle, or perhaps just the shock of seeing their whole purpose destroyed, turned them mad; since that day both Abbendis and Isillien have been quite insane.Can you not see it, brothers and sisters? There is but one way to wipe the Scourge from the face of Azeroth. The Scarlet Crusade offers you the protection that you so desperately desire, and if you will pledge yourselves to us, surely we will reach our ultimate goal. Defy us, and you will be dispatched in a blaze of golden light unlike any you have ever witnessed...
— Scarlet Commander Renault Mograine
At the beginning of the Third War, the Order of the Silver Hand was suspended by one of its own members, the Prince of Lordaeron Arthas Menethil, as Uther refused to purge the city of Stratholme infected by the plague. Although the paladins continued to fight against the Scourge, the Order and its leadership were decimated by the traitor prince during the fall of Lordaeron, and Highlord Alexandros Mograine succeeded the late Uther to organize the resistance. As the original wielder of the Ashbringer, Alexandros became a symbol of rallying against the undead, until he was betrayed due to the machinations of the dreadlord Balnazzar and the Arch-Lich Kel'Thuzad. His death shattered the Silver Hand, who eventually split up between the later formed Argent Dawn and the Scarlet Crusade for ideological reasons.
Abbendis and Isillien wandered the area as the Scourge defiled the land, destroying what undead they could, gathering what warriors would join them. They had but one concern: eradication of all that had destroyed Lordaeron. They were joined by young Taelan Fordring, one of Isillien’s protégés, who adored his tutor and his general. He offered his family’s keep and land, untouched by the undead, for their base of operations. The elder Abbendis and Isillien felt that although they had a good base, they really needed to attack the Scourge where they were the thickest: in the Eastern Plaguelands. Isillien took on the title of Grand Inquisitor, while the elder Abbendis led the majority of the forces to Tyr's Hand in the east to strike at Stratholme. As they established their bases and took in many more warriors, they destroyed any undead they found.
Together, the elder Abbendis and his daughter, Isillien, Saidan Dathrohan (Balnazzar), Renault Mograine, and Taelan Fordring unaware of the true scale, the atrocities committed by the Crusade only if not for his father who eventually helped him see the truth, founded the Scarlet Crusade to fight back against the undead they saw as having corrupted Arthas and destroyed their order.
Once a wealthy human landowner in Stratholme, the plague corrupted Rivendare and he pledged himself as a death knight.
Rivendare’s duty is to round up and murder any human survivors he can find, and he and his patrols do just that.
He fell under Kel'Thuzad's sway and helped build and structure the Cult of the Damned. Rivendare then achieved the title and powers of a death knight. Now, Rivendare has his base in Stratholme. He serves Kel'Thuzad eagerly and exults in his power. One of his greatest joys is to instill corruption in others, especially paladins, and most especially members of the Argent Dawn. This knight is a regal figure — his face is pale but aristocratic, and white hair hangs to his shoulders, while a scarf covers his face. He crouches over a horned, skeletal steed, and purple runes glitter across his black armor, cloak, and runeblade. Baron Rivendare excels at melee combat (especially mounted warfare) and he knows it. At the earliest possible moment, he charges, whether afoot or mounted on his skeletal horse, Deathcharger. Then the baron unleashes the dreadful power of his runeblade. He prefers to fight with created undead to support him, and he uses death pact on these to recover hit points. Rivendare enjoys testing his mettle against fellow close combat specialists, but strikes at arcanists and healers if they prove bothersome.
During the siege of Blackrock Spire in the Second War, Highlord Alexandros Mograine found a mysterious, dark crystal on the body of a dead orc warlock from Draenor. The crystal was described as a "living embodiment of shadow".
Mograine kept the crystal a secret for years until just before the Scourge invasion of Lordaeron. He revealed it to the other leaders of the Silver Hand, suggesting that they try to find the crystal's antithesis — a manifestation of the Holy Light itself — that could be used against the impending undead invasion. Mograine's peers were appalled at the sight of the dark crystal and tried to destroy it with holy spells. Unexpectedly, the crystal absorbed the spells and became the crystal of pure light that Mograine mentioned moments before. The group agreed to forge a weapon from the crystal that would smite the undead with such power that only a cloud of ash would remain in its wake.
Days later, Mograine and his advisor Fairbanks traveled to Ironforge to visit King Magni Bronzebeard with the unique crystal of pure light. They gave their condolences on Muradin Bronzebeard's fate in Northrend, and asked him to have a weapon forged from it. To avenge Muradin, Magni personally took on the task and forged the Ashbringer to oppose Frostmourne, Arthas, and the undead. While Magni never took much stock in the belief that Master dwarven blacksmiths could impart emotions into the weapons they create, standing before The Great Anvil, he found himself thinking of how he would not see Muradin again. He thus harnessed all of his rage, fury, the desire for vengeance, and willed them into being with each strike of his hammer. It is said he worked for three days straight.
After Arthas' betrayal, the remaining leaders of the Silver Hand banded together to fight the undead of the Plaguelands. The Ashbringer became the most lethal weapon in their arsenal — and it quickly garnered the attention of Kel'Thuzad. The dreadlord Balnazzar (in the newly-possessed body of Grand Crusader Saidan Dathrohan) sought to manipulate the remnants of the paladin order to advance his goals for the Burning Legion. After Mograine stated his intentions to attack the Undercity, Balnazzar put plans into motion to eliminate Alexandros (ostensibly to protect his brother, Varimathras, who was in the Undercity secretly manipulating Sylvanas Windrunner and her Forsaken).
Therefore, Balnazzar made a pact with Kel'Thuzad to eliminate Alexandros and end his threat to both of them, he corrupted one of Alexandros' sons, Renault Mograine, and set a trap for the Highlord. Renault led his father and Fairbanks to Stratholme, where legions of the Scourge awaited them. During the battle, Renault hid while Alexandros and Fairbanks fended for themselves. At some point, Fairbanks eventually became trapped alive under a pile of corpses, while Alexandros alone continued to smite thousands of the undead, but eventually became weary and dropped Ashbringer. Renault came out of hiding and slew his father with the sword, which corrupted the blade.