During the Third War of the Races, Brona's army of Trolls and Gnomes, led by Skull Bearers, burned Kern and passed over the Mermidon River and surrounded the city. An aid of Elven archers came from Arborlon, but the odds were still against Tyrsis.
At dawn the enemy sounded the Death Watch, signaling their intention to destroy the city and everyone within her walls that day. The battle bagan slowly as if the enemy was toying with the defenders. The armies massed for the attack under the sound of wardrums as the skies blackened. A battalion of Trolls charged the gate with a huge ram under the hail of arrows, that was inadequate to stop them. The gates broke and the monsters charged forward against the last defenders.
In the meantime Shea Ohsford confronted Brona in the Skull Mountain and slew him with the Sword of Shannara. Then the earth shook and thunders echoed. The Skull Bearers vanished shrieking and the darkness dispersed. The enemies retreated and the Third War of the Races was over. Shea donated the Sword which was kept in a Vault in Tyrsis as a monument to those sacrificed, and a testament of the power of freedom.
20 years later, a flame barrier appeared around the Vault which every night attracted Walking Corpses that swarmed the walls. The Border Legion tried to clean up the weakest regions. When the guards saw that their casualties joined the undead, they stopped fighting and simply avoided them, shutting them out of the walls.
After several weeks, one night Jak Ohmsford came with Shella Leah, sent by Allanon to warn Balinor of Brona's return and to retrieve the Sword of Shannara. With the help of the Dwarf Brendel they cast the Spell of Disruption, saving the city from the plague.
After Brona's destruction, the heroes gathered to Tyrsis and Balinor led the ceremony to reseal the Sword in the Vault.