Gustav Ziestack is the manager for the Treasures of Egypt Exhibition. He is a good friend of Jasper's and an old colleague of Mr. Sweet. He appeared often in Season 2 but is not a main character. He first appeared in House of Spirits / House of Blackmail when Victor and Mr. Sweet were giving him a tour of the school. Victor was practically eating out of his hands and bowing, causing the students to laugh and make fun of him after he and Gustav left. In House of Combinations / House of Heartbreak, he was at the exhibition to watch the students' presentation. He ended up giving them the exhibition. He also attended a dinner at Anubis House in House of Trades / House of Magic and House of Tricks / House of Whispers, where he found Alfie's magic tricks to be very entertaining and Victor to be a bit strange. He attended the End of Exhibition party held at Anubis House in the Season 2 finale. He seemed to not notice the trouble that the Anubis students cause. He thought that they did it on purpose instead of by accident. He did not appear in Season 3, nor was he mentioned.
He was portrayed by Hugh Lee.