Regeena Peterson (Voiced by Leah Cudmore) is a new character introduced in the third season, titled Mission: Earth, who quickly befriends Betty and Noah. She is the daughter of Principal Peterson, and, as far as he's concerned, she's a sweet, demure, respectable girl. But as soon as he turns his back, her real personality comes out, which is quite the opposite. Betty finds Reegena refreshing, around Regeena, she comes out of her shell. In fact, Betty becomes a bit of a project for Reegena; She is determined to make Betty get out and "do stuff!". She has a somewhat bulkier build than most of her classmates, but given her father's athletic interests and build it's quite likely that this is muscle as opposed to fat.
Regeena has a distaste for Penelope, after Penelope's attempts to woo her upon hearing that she is Principal Peterson's daughter (she wants Regeena to be her friend only to raise Penelope's own social status). In later episodes, Regeena is often suspicious of Betty, Noah, or Sparky when they unexpectedly leave for missions, though she often takes their disappearances in stride.