The Star Cluster, also known as Kingdom Key W (キングダムチェーンW, Kingudamu Chēn W?, lit. "Kingdom Chain W") and The King's Keyblade (王様のキーブレード, Ō-sama no Kīburēdo?), is a combination of Mickey's other two Keychains, Star Seeker and Kingdom Key D, in Kingdom Hearts III.
Kingdom Hearts III
With the Star Cluster in hand, Mickey and Riku return to the Dark Margin to find Aqua, only for Mickey to be restrained and disarmed by another Demon Tower. Anti-Aqua emerges from the Tower, picks up the Star Cluster, and wields it against Riku and Sora.
After Sora frees Aqua from the darkness, Mickey resumes usage of the Star Cluster, wielding it during the clash between the seven guardians of light and the thirteen seekers of darkness.
The Star Cluster is modeled after the Kingdom Key D and, by extension, Sora's Kingdom Key. It features a gold handguard, and a blue blade patterned with stars in the manner of the Star Seeker. The concave rainguard has now been replaced by a diamond-patterned bell shape. At the top two corners of the handguard are five-pointed star designs, while the bottom two appear to have massive golden screws. Between the handle and the rainguard is a glass-like dome, deep blue and speckled white like a starry sky, and on the guard below the handle is a gold crescent moon. The teeth of the blade are now silver, and the crown shape is lined. The Keychain is unchanged from that of the Kingdom Key D; it has golden links connecting to a golden Hidden Mickey.