Stephanie Gaunt is the main antagonist of the Wizards vs. Aliens episode Friend or Foe.
Stephanie was an Unenchanted (non-magical) woman who owned a hi-tech company Gaunt Technologies (but kept herself out of the public eye) and wanted to prove magic existed so she sent one of her employees Adams to kidnap a wizard named Tom Clarke and also takes a Nekross named Lexi (who was disguised as a human woman named Lucy). After finding out Lexi was an alien Gaunt decided to try and use Tom's magic and Lexi's Nekross technology for world domination and tries to get them to teleport the Crown Jewels to her but Tom and Lexi work together and trick Gaunt and escape. Gaunt is then taken by Lexi to the Nekross's ship The Zarantulus where she meets the other Nekross including Lexi's father The Nekross King who she tries to get to ally with her but he refuses and Gaunt is fed to his pet Skorpulus.
She is played by Ruthie Henshall.