Yy

 was an angel who fell from Heaven after failing to announce its relocation to all of creation. Instead he became corrupted and sold his wings for a cheeseburger. He was imprisoned on the planet Sheol, location of the tourist attraction Heaven.

Yy was discovered by Peri, who had been killed by a group of putti so that she could see Yy and convince him to finish his job. The putti restored Peri to life so that she could help Yy close the Gates of Heaven. When that was accomplished, the putti took Yy to the real Heaven, though he didn't get his wings back. (PROSE: The Ruins of Heaven)