In Dark Souls, the Broken Pendant is the key item needed to enter the downloadable-content area through the Darkroot Basin portal.
The item is obtained from a Crystal Golem in the Duke’s Archives. After acquiring it, the player can return to the lake in Darkroot Basin, where a black hole-like portal appears near the area’s hydra. Interacting with the portal transports the player to the past, beginning the Artorias of the Abyss adventure.
The Broken Pendant is easy to miss because the game does not announce its purpose immediately. Its description and the portal’s appearance encourage exploration rather than giving a direct quest marker. It is not the same object as the normal Pendant starting gift, which has no role in opening the DLC. The DLC expands the history of Oolacile, introduces new bosses and characters, and explains more about the Abyss. The item’s name reflects the fragmentary, time-displaced nature of that story.