Cagliostro

Cagliostro was the author of mystical grimoire known as the Book of Cagliostro.

Biography
Sometimes in the past, the man known as Cagliostro came in contact with the Mystic Arts. He was able to study the Eye of Agamotto, learning the spells and the gestures necessaries to properly use it, as well as the power of the relic over the time continuum. He also learned the secrets and the dangers of the Dark Dimension and his ruler, Dormammu. He eventually write down his knowledge on a book, that was still held in the library of Kamar-Taj many years later, as a part of the Ancient One's private collection.

Trivia

 * In the comics, Cagliostro was one of the many aliases through history of a sorcer who achieved immortality with the knowledge of the Darkhold. He was also known as Giuseppe Balsamo, an Italian alchemist, and was a teacher of Victor von Doom and an enemy of Doctor Strange. Cagliostro was also an alias used by the time traveling sorcerer Sise-Neg.