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This article contains plot details from the latest books.
Lord Cassius is Keefe's father, and part of the Sencen family. He works for the council and is a powerful empath. Lord Cassius's wife is Lady Gisela. In Keeper of the Lost Cities, he meets Sophie briefly on the staircase leading down from the Level Four wing, on the end of Midterms celebration. He took quite an interest in Sophie Foster, hinting that he knew she was the mystery prodigy that Sir Tiergan was Mentoring. Lord Cassius thinks Keefe should stop wasting his time and work harder in school. Lord Cassius wrote a book about Empathy, called The Heart of the Matter. Keefe, who had to read it in Book Four, described his father as a "torturer of innocent readers." He is also told to be not a great father, and has constantly belittled his son, Keefe.
His name, Cassius means "empty", or "vain", referring to his character.
Lord Cassius is described as taller man with much of Keefe's characteristics, but with blonde, slicked back hair and neater attire.
During Book 3: Everblaze, Keefe believes Lord Cassius works for the Neverseen when in fact it is Lady Gisela working for the evil organization. Lord Cassius was completely blind to the fact that she was manipulating him.
After being betrayed by his wife, Lord Cassius, and a few telepaths search through his memories for any information about the Neverseen.
In Book:6 Nightfall, Lord Cassius tells Keefe and Sophie where Vespera hid her signature in Atlantis, proving he is somewhat worthy to be apart of The Black Swan, which he later joins.