From the Kingdom Hearts Wiki
Master Form is obtained in the second episode of Hollow Bastion after Sora and crew speak with King Mickey before the Battle of the 1000 Heartless and during the events of Space Paranoids. It requires 4 bars of the Drive Gauge to activate, and is considered a combination of both Valor and Wisdom forms. Master Form utilizes two Keyblades, one levitating through telekinesis, and the other in-hand with an intense electricity flowing through it. It specializes in both Magical and Physical combat, and performs strong and wide-ranged aerial combos exclusively. Its special ability is Aerial Dodge, a midair jump that blocks attacks (and reflects projectiles). Sora wears yellow clothes with a sans cross motif. In Halloween Town, it's represented by two halves of Valor and Wisdom Forms' emblems stitched together. It is based on King Mickey and uses both partners.
Also fun fact, since the picture in the wiki has Sora with the Kingdom Key and the Oblivion, I decide to have Sage use her base keyblade/the green one known as "Natures voice" and the Oathkeeper/the white one
