Cavendish (キャベンディッシュ Kyabendisshu ) is the surname of a prestigious and aristocratic witch family from Britain with a history dating back to the 6th century. They are highly respected and have great influence in the magical world. Their family estate is the Cavendish Manor, located in Wedinburgh. The Cavendish line of witches is known both for their wisdom and their kindness. Their motto is "Affection" and their patron animal is a white unicorn. They specialize in healing magic.
The House of Cavendish originated in the 6th Century, being established by one of the Nine Olde Witches, Beatrix. From the Middle Ages to the last war, the Cavendish used their magic to heal people regardless of whether they were allies or enemies. They kept these practices secret because of those who disagreed with them.
Family leadership has been inherited by generations of witches along the maternal line. This role can only be inherited in a ceremony during a Venusian Eclipse that only happens every many years, and it is said that a horrible calamity falls on all that interfere with the ritual.
Currently, Diana Cavendish is the legitimate heir apparent. However, due to the death of her mother when she was quite young, Diana's aunt Daryl Cavendish and her daughters became the proxy heads of the household until Diana was old enough to take over. The period of Daryl's leadership has been one of the declines for the family. She has little regard for their history and thinks magic itself is obsolete, and she has sold countless precious artifacts held by the family, often at discounted prices. She believes this practice is necessary to sustain the family, unlike her elder sister, who assisted others for free.
Years later, Diana, now old enough to put a stop to Daryl, selflessly decided to leave her beloved Luna Nova Magical Academy and save the family from extinction by becoming its head despite Akko's initial protests. She was unable to complete the ascension ritual however, due to stopping by to heal Daryl, Maril and Merrill from being completely affected by cursed calamity for iinterfering. Despite this, such act of kindness earned Diana the approval and gratitude of Beatrix's spirit and in turn, allowed Daryl and her daughters to realize their errors and gained a better outlook over their family and magic's future, confident that Diana would be able to restore their family's former glory one day.
The Cavendish family members are characterized by their blond hair with greenish highlights and blue eyes. They tend to inherit great talent in magic (especially healing magic) in their bloodline.
- Beatrix Cavendish (founder)
- Bernadette Cavendish
- Diana Cavendish
- Daryl Cavendish
- Maril Cavendish
- Merrill Cavendish
- Cavendish is a British noble family that has been one of the richest and most influential aristocratic families in England since the 16th century. 
- The Cavendish surname might also be a reference to Richard Cavendish, a British historian, who wrote a few fairly popular books dealing with magic and the occult. His most famous works being the The Black Arts: A Concise History of Witchcraft, Demonology, Astrology, and Other Mystical Practices Throughout the Ages and the 24 volume Man, Myth & Magic series. 
- The Cavendish have a lot of secret spells that are only meant for members of the family. Some of these spells must be in risk of disappearing because they need the user to be an expert witch, have Cavendish blood and have accepted Beatrix's ideals in her heart.
- Throughout the episode: "Intelligence and Sensibility" , it appears that wands used by members of the Cavendish Family have a serpent interwined in the handle, this is likely a reference to the Rod of Asclepius, from greek mithology, which is a serpent-entwined rod wielded by the Greek god Asclepius, a deity associated with healing and medicine, which is the specialization of magic the family is famous for.
- The only expection to this is Diana, in that same episode, who is using the standard apprentice rod of Luna Nova, although, she did use a rod with a serpent during her childhood.