It was during the defense of Quel'thalas that the ancient blade and its wielder were ultimately cut down. Anasterian fought well against the undead prince, using Felo'melorn to temporarily cut down Arthas's steed, Invincible, which enraged the death knight and caused him to fight with increased fury and rage. The wrath of Arthas Menethil, combined with the power of the ancient runeblade Frostmourne, battered the elven King and shattered Felo'melorn. In the end, Anasterian was cut down by Arthas, although even with his blade now broken, the elven king did not give up the fight, even managing to bury the blade into Arthas's thigh.
Shortly after the defeat of Quel'thalas, the shattered remains of Felo'melorn and the body of Anasterian were recovered and returned to Silvermoon, with Anasterian's son, Kael'thas Sunstrider, ordering the magical blade to be reforged. It then became Kael'thas's personal weapon, which he carried with him as he fought first under Lord Garithos, and then under Illidan Stormrage. When Illidan and his allies attacked Icecrown Citadel, the fortress of the Lich King itself, Kael'thas ended up facing his father's killer, Prince Arthas. The two fought, with Kael'thas boasting that elven blades became stronger when reforged. This boast proved true, for when Arthas brought down the fury of frostmourne on the elven prince he was surprised when Kael'thas was able to block the attack without shattering the blade as it had done when it was wielded by Anasterian. Eventually, Illidan and his forces were forced to retreat, and during the chaos of the battle, the ancient blade was lost by Kael'thas.
After the betrayal of Kael'thas Sunstrider, which saw the elven prince join the Burning Legion and attack Silvermoon itself, a distant relative within the Sunstrider line, Lyandra Sunstrider, traveled to Icecrown in an attempt to recover the ancient blade. While she found the blade, she was ultimately cut down by the undead scourge and reanimated as a servant of the Lich King. Later when the Burning Legion invaded Azeroth once again, the Tirisgarde, recently reformed by Meryl Felstorm, sent skilled mages to recover several powerful weapons, with Felo'melorn being one of the three. The mage sent after the ancient blade infiltrated Icecrown Citadel and after some searching found the undead form of Lyandra Sunstrider. In the battle that followed, the undead Sunstrider was cut down and Felo'melorn was recovered and returned to the Tirisgarde vaults where it currently remains.