The Sencen family used to be very powerful in the Elvin world, but they lost credibility after Lady Gisela was revealed to be in the Neverseen. Lord Cassius was said to be a big part of Elvin security. Keefe is part of the family, along with Lord Cassius, Keefe's father, and Keefe's mother Lady Gisela. They have a huge home/skyscraper named Candleshade, but Lord Cassius and Keefe currently live at Shores of Solace, with Lady Gisela's location unknown. In the books it is described that Lord Cassius is cold and cruel, and is very critical of Keefe. To avoid his father, Keefe often goes to Everglen, or Havenfield. It was also revealed in the series that Lady Gisela was a member of the Neverseen, and was a criminal mastermind who played everyone to believe that she was a member of the nobility and nothing more.
Lord Cassius and Keefe have always had a rocky relationship, but Lord Cassius asked Keefe to come live with him in Nightfall at Shores of Solace (his beach house), as part of a deal for information on Nightfall's location. Another part of the deal was that Lord Cassius could join the Black Swan.
Lady Gisela is no longer considered a member of the Neverseen after King Dimitar's torture of her in Neverseen, which was apparently ordered by an elf, as revealed in Nightfall. She worked, with requests for her own kinds of assistance, to help them find Nightfall and rescue Sophie's parents; however, at the end of Nightfall she formed/forced an alliance with Vespera.