Petrello was the seventh child of the Red King. His endowment allowed him to control all storms. He could summon wind, thunder, lightning, hail, snow, produce fogs, control water and summon tidal waves, typhoons, and drown people. His descendants include Dagbert, Lord Grimwald, Mr. Torsson, and Tancred. He was considered bright by the Red King in the prologue of the fifth book and was one of the good children. He fled the castle with his other good siblings when their mother died and the bad siblings took over the Red King's Castle.
- It's possible that Petrello was dyslexic, as in Leopards' Gold Nurse Ogle mocks him for not being able to write his letters correctly.