- "This was the old banqueting hall where my great-grandfather bade seven hundred nobles to a feast and killed them all before they had drunk their fill."
- ―Jadis, describing her ancestor (Chapter 5) [src]
Jadis' great-grandfather was one of the late rulers of the world of Charn. Little is known about him, other than he was the third last legitimate Emperor, and was a cruel, murderous and quite possibly insane and sociopathic man, just as many of Charn's last monarchs were.
He once bade seven hundred nobles to a feast, but killed them all before they had even drunk their fill of wine. He did this simply because they had all had "rebellious thoughts".
- The Banquet Hall, where Jadis' great-grandfather had killed all the nobles, was located near the Dungeons and Principal Torture Chambers before Charn's destruction.
- From the description given of the last rulers of Charn, with faces of those who has done or suffered something dreadful, it is possible that Jadis' great-grandfather received a similar fate.
- From how he was described by Jadis, her great-grandfather obviously had the power to look into people's minds and read their thoughts. It is not known for certain if Jadis had the same trait as he, but considering the magic that ran through their family's bloodline it is definitely possible. Plus, there were some scenes when she spoke to Digory Kirke and his Uncle Andrew, and seemed like she was able to see into them.
- In the illustration by Pauline Baynes, where Jadis first awakens on Charn, you can make out what must be her great-grandfather in the Hall of Images. As Jadis was the last one seated, you can see her empty seat where she must have been sitting, and then (going backwards) you see what must be her father, grandparent, and finally her great-grandfather.