Star Cluster

The Star Cluster, also known as the Kingdom Key W (キングダムチェーンW) and The King's Keyblade (王様のキーブレード), is the default form of Mickey's third Keyblade in Kingdom Hearts III. It is a combination of Mickey's first two Keyblades, the Star Seeker and Kingdom Key D.

Kingdom Hearts III
After Mickey's Kingdom Key D is damaged during a fight with a Demon Tower, Mickey and Riku go to the Mysterious Tower to receive upgrades.

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 wielding the Star Cluster during the clash between the seven guardians of light and the thirteen seekers of darkness.

Design
The Star Cluster is a fusion of the Kingdom Key D and Star Seeker, though its design is based on the Kingdom Key D. 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 The concave rainguard has now been replaced by a diamond-patterned bell shape.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.