John Dee (ジョン・ディー Jon Dī) is Camio's butler and the only current member of his Household. He was a mathematician, astronomer, astrologer, occult philosopher and imperialist, and devoted his life to the study of alchemy, divination and Hermetic philosophy.
He appears to be tall, with light coloured hair that has darker roots. He wears wide, black rimmed, glasses, and has a Nephilim marking that looks like a third eye on his forehead (when in his demon form).
John appears to be quite cunning, with a possible ruthless streak. He cares deeply about Camio, and became a demon so the aforementioned would not be lonely anymore. He had an interest in demons when he was a human.
John originally grew up in London and became a low level bureaucrat. He met Camio when he was five, their second meeting was close to ten years after when he was performing a demonic ritual and he asked him to be his friend. They studied in the same school, Stratford, and grew quite close, Camio was close to admitting to him that he was a demon a few times.
He is said to have discovered the Enochian language (by coming into contact with Uriel), and became a favourite of Queen Elizabeth. Near the end of his life, Uriel came to make him ascend - however John refused him. He had a symbol on his arm that drew the angel away, and formed a pact with Camio, becoming a demon.
An astrologer who was active in the 16th century. Moreover, he’s also a scholar who is proficient at maths and navigation. Became an associate college professor at young age, that achievement was acknowledged by royal family and he became a scholar at the court. He began researching astrology, made horoscopes for Mary and Elizabeth who fought over the throne. Due to that, current Queen Mary I suspected him and he was imprisoned.
During that time, Dee’s prediction of Queen Mary’s time of death and Queen Elizabeth enthronement was completely realized. After he was released, while he was traveling through various european countries, he started to become interested in angel summoning. A person named Edward Kelley was arranged to be his assistant. That assistant communicated with the angel Uriel, and with the language he had written down, he composed the enochian language. Later, that was incorporated as magic by Hermetic Order of the Golden Dawn, led by Mathers.
Isaac: According to the history books, Kelley was considerably wild …kind of. You skillfully made a guy like that as a assistant.
Isaac: Member of a gang, or indulge in prostitutes…
John: That’s true. John: However more than be able to see spirits, he was handsome.
John: It can’t be helped when he is handsome. After all, he is handsome.
Isaac: Eh? The reason I’m refused household is, perhaps…” 
- John mentions on several occasions that Camio's Household (which was started with himself) is five hundred years old, however, he can't be more than three hundred years old (going by the time he lived in). The manga is ether stationed around the year 1971 (going by the Paris incident in Pillar 32) or the year 1888 (the appearance of Jack The Ripper in Pillar 46 - Pillar 48)
Amon and Mamon • Baphomet • Eligos • Gilles de Rais • Gilgamesh • John Dee • Lamia • Leonard
Belphegor • Empusa • Lamashtu • Leviathan • Lucifel Rofocale • Pluto • Astaroth the Second • Behemoth
Adrian Swallow • Barton Twining • Bianca Clifford • Elliot Eden • Mary • William Wynn Westcott
Arthur Christian • Cassandra • Ernest Crosby • Tamar • Elizabeth Dale