The Star Seeker (スターシーカー Sutā Shīkā?) is a Keychain for Sora's Keyblade and Mickey's Keyblade that is found in Kingdom Hearts II, Kingdom Hearts 358/2 Days, Kingdom Hearts coded, Kingdom Hearts Birth by Sleep, their remakes, and Kingdom Hearts Re:Chain of Memories. In Kingdom Hearts 358/2 Days, it can be upgraded to the Star Seeker+.
In Kingdom Hearts II, Flora, Fauna, and Merryweather give Sora the Star Seeker, along with his new clothes, as the Keyblade for his new Valor Form. The Star Seeker is not initially available for Sora to use in his standard form, since it is set within the sub-weapon slot for Valor Form. As Sora must have a Keyblade in that slot at all times, the Star Seeker cannot be switched out until he obtains a third Keyblade.
In Kingdom Hearts Birth by Sleep, this is the Keyblade that King Mickey used while he was apprenticed to Yen Sid. King Mickey also wields this Keyblade within Kingdom Hearts coded, and can equip it within Mission Mode in Kingdom Hearts 358/2 Days.
The guard appears to be two shooting stars. The blade is blue and decorated with stars, while the end is a crescent moon and star. The Keychain design is a crescent moon. The Keyblade's name seemingly references Mickey and Sora's journeys to the various worlds, which are seen as stars. It also makes a reference to the worlds in the universe of Kingdom Hearts, since stars refer to the worlds.
The Star Seeker is part of a group of weapons associated with the Mysterious Tower, along with the corresponding staff and shield. These weapons are decorated with crescent moons and stars, and are the second set of weapons available to the party.
King Mickey can equip this Keyblade in Mission Mode in Kingdom Hearts 358/2 Days by equipping the Pandora's Gear. The ground combo for this weapon starts with a horizontal slash to the left, followed by a horizontal slash to the right, a spinning slash, and ends with a large jump to the left with a dashing slash back to the right.
The aerial combo consists of a horizontal slash to the right finishing with a vertical slash upward, followed by the upward slash leading into a 360 degree spin with the Keyblade held above the King's head, and ends with a series of three thrusts as you descend.
In Kingdom Hearts II, the Keyblade has the innate ability Air Combo Plus, allowing Sora to use air combos for a longer period of time. Later in the game, the Star Seeker's strength becomes eclipsed by other Keyblades, and as such, this Keyblade still has some purpose as the secondary Keyblade of either the Valor, Master or Final forms - and if paired with the Hero's Crest, the Star Seeker can prolong the enhanced air combos used and deal far more damage.