Battle Fort is an extra level and a multiplayer that was added exclusively to Super Mario 64 DS. Note that in the main adventure, the level was referred to as The Secret of Battle Fort. The entrance to the level is located in the courtyard of Peach's Castle, underneath three Brick Blocks, with the Boos. As Yoshi cannot destroy Brick Blocks, either Mario, Luigi, or Wario must enter instead. The level consists of two main floors, the bottom of which is patrolled mainly by Heave-Hos and a Chuckya. On the bottom floor, there are also rolling balls that look similar to Big Steelies. Other enemies include Goombas and Bob-ombs In multiplayer mode, all the enemies were removed, except the black rolling balls (which only Wario can destroy). Like Sunshine Isles, there are yellow boxes with feathers which any character can use.
Star 1: 5 Silver Stars
There is only one Power Star to collect in this area, in which the player must collect the five Silver Stars scattered around the level while avoiding the enemies and obstacles. After collecting them all, the Power Star will appear in the Star Sphere near the player's starting position. This is one of the only two secret levels, along with Sunshine Isles, to have only one Power Star.