Mildred is the fairy godmother of Slumberland.
In Griddle's Sleepless Knights, she gave Flicker and Sir Loungelot pajama-style outfits for Slumberland and told them to be quiet in the Shush Zones. Loungelot repeatedly kept yelling and was punished by Mildred each time. When shooting a beam of magic at him, she accidentally destroyed Mr. Sandman's castle.