In Dark Souls, the starting gift that opens many locked doors throughout Lordran is the Master Key.
The Master Key is one of the gifts available during character creation. It functions as a reusable key for several doors and shortcuts, allowing players to reach certain areas earlier than intended. This makes it especially popular with experienced players and speedrunners.
The key does not open every locked door in the game. Some doors require unique keys, special items, or progress through a particular event. It also does not replace the ability to obtain ordinary keys during the adventure.
A common mix-up is confusing the Master Key with the Thief starting class. The Thief begins with the Master Key automatically, while other classes can select it as their gift. The choice can significantly change the early route through Lordran.