Dungeon Siege II

The game begins with the player-controlled protagonist and their friend, Drevin, serving as mercenaries in the army of Valdis, a warlord who has aligned himself with a race of Dark Wizards and wields the magical Sword of Zaramoth. The player character and Drevin are ordered to capture a temple held by dryads. After the temple is captured, however, Valdis attacks the mercenaries. Drevin is killed, and the player character is knocked unconscious.
The player character regains consciousness in the custody of the dryads. Rather than execute them, the dryads allow the player to earn their freedom by helping them in the war against Valdis. After the protagonist earns freedom, they discover that they are infected with the Plague, a mysterious disease created by the Dark Wizards that drives its victims to insanity. After being cured by the water from an Elven shrine, they return to their hometown.
On the way home, the player character rescues an old man from Plague-maddened dryads. The old man describes an event called the Great Cataclysm, caused when the Sword of Zaramoth that Valdis wields struck a magical shield called the Shield of Azunai. The blow shattered the shield, causing a catastrophe that ended the First Age. Valdis hopes to cause another such catastrophe by gathering the shards of the Shield of Azunai so he can shatter it again. The old man explains the Plague, saying that it is caused by crystals created during the Great Cataclysm that give license to the souls of Zaramoth's army to possess the living.
After the player character returns home, they begin to gather the pieces of the shield to use it against Valdis. After they gather all of the pieces, they take them to the Agallan giants so that they can re-forge the shield. As they re-forge it, they place a medallion in the center of it for added durability. This medallion had previously been worn by Drevin; he gave it to the player character before he died.
With the shield re-forged, the player character travels to Valdis' stronghold known as Zaramoth's Horns. The shield protects them from the Dark Wizards, but the battle with Valdis himself proves to be a stalemate until the old man appears and takes the shield from the player character. He gives the shield to Valdis, revealing that he is a Dark Wizard. Valdis tries to destroy the shield with the Sword of Zaramoth, but when he strikes the shield, his sword shatters instead. Valdis and the player character resume the battle, in which Valdis is killed.