Castle Dedede, is a recurring location in the Kirby series. It also appeared in SSB Brawl's Subspace Emissary. As can be guessed by the name it is the Residence of King Dedede. Though it is a location in the emissary it is never explored and is shown only in cutscenes.
The first time the castle is shown is after Dedede stole the trophies of Ness, Luigi, and Peach/Zelda from Wario. He puts them in the throne room and gives Ness and Luigi his Dedede Brooches. He then reluctantly gives Peach/Zelda his own badge, and plans to make another later. Suddenly Bowser's Koopa Troop attacks the castle and they knock out Dedede and steal Peach/Zelda. As a final act a Subspace Bomb then explodes sending the castle into Subspace.
As with all locations it is restored in the end.