The Ruler of the Sky is a minor villain in the video game Kingdom Hearts 358/2 Days. It's an Emblem Heartless that resides in Neverland.
As Roxas arrives at Neverland, Pete shows up and brags about his plans for creating an army of Heartless, and threatens to have his Heartless gobble Roxas up for interfering at Agrabah. While that was going on, both Captain Hook and Smee finally finished digging up a treasure chest along with a giant bird skull and a golden sword. Just as Pete had been planning, the darkness of Hook's greed summons a Heartless in the form of that treasure known as the Ruler of the Sky, and the pirates flee for their lives after witnessing the giant Heartless. Roxas was forced to fight the risen Heartless.
After a long battle, Roxas managed to defeat the Ruler of the Sky in an aerial battle. As the Heartless fades, it plummets into the Pirate Ship, destroying it, then releases its captive heart.