|Relationships:||Thomas Cahill- ancestor (deceased)|
|First Appears In:||The Black Book of Buried Secrets|
|Last Appears In:||The Black Book of Buried Secrets|
- Thomas Cahill - Ancestor (deceased)
- Jane Cahill - Ancestor (deceased)
- Luke Cahill - Ancestor (deceased)
- Katherine Cahill - Ancestor (deceased)
- Madeleine Cahill - Ancestor (deceased)
- Olivia Cahill - Ancestor (deceased)
- Gideon Cahill - Ancestor (deceased)
PersonalityEditIvan Kleister does not like the Holt Family, and is skeptical of their Clue-hunting abilities. He even is willing to give bonus rewards to those who can lock the Holts in their basement. However, that may have changed.
At the back of the book, there is a letter from Ivan Kleister to all Tomas agents. It reveals that Ivan has a rivalry with the Holts.
In this book, Hamilton and his family go to Mt. Fuji and try to explain why they had given away their Clues. However, Ivan starts insulting the Holts, resulting in Madison butting his stomach with her head and him falling off the balcony. The rest of the Tomas attending then ask to hear what Hamilton had to explain.
- He is a popular extreme sports superstar.
- Since he is a renowned hockey and boxing player, it says that his right hook is better than his leadership skills.
Ivan does not appear online.
Ivan's main card is Card 188.File:Card188.jpg