Zealots
The Zealots were a break-away sect of the Masters of the Mystic Arts who objected to the limitations placed on the order by the Ancient One and sought access to forbidden magics.
History
Kaecilius joined the Masters of the Mystic arts after the loss of his wife and son. Although the Ancient One sought to ease his grief through spiritual training, Kaecilius was not able to come to terms with the deaths, and became fixated on the idea of using magic to bring them back to life.
He began approaching other members of the Masters, finding those who shared his discontent with the order's restrictions on the magic they could learn. This group became the Zealots.
The Zealots broke into the House of Wisdom, seeking forbidden books. In the course of the theft, they were confronted by the Librarian, and Kaecilius killed him to conceal the theft. They stole the Book of Cagliostro but were caught by the Ancient One.
They fled through a portal to London but were forced to stand and fight their former teachers. As novices, they were outmatched, and most of the Zealots were killed. However, Kaecillius and the four remaining Zealots were able to escape with the book.
Not knowing what it did, Kaecilius recited a spell from the book, finding it granted himself and his followers more powerful magic and additional magical abilities. Unbeknownst to them, the spells in the book related to the Dark Dimension and the power they recieved came from Dormammu.
Newly empowered and furious at the death of so many of their number at the hands of the Masters, the Zealots swore to destroy the Masters and the Ancient One.
Their first target was the London Sactum, where Kaecilius challenged the Sanctum Master Sol Rama to a duel. Realising he was outmatched, Rama attempted to escape through a portal to Hong Kong. Before he could escape however, he was stabbed by one of the Zealots, killing him. They then proceeded to destroy the Sanctum.
Following their success in London, they attacked the New York Sanctum, killing the Sanctum Master Daniel Drumm. They were confronted by Stephen Strange, who despite being outmatched was able to strand two of the Zealots in remote parts of the world using portals.
Strange was eventually able to subdue Kaecilius using the Cloak of Levitation and Crimson Bands of Cyttorak, but the Zealots whom Strange had teleported away returned, stabbing strange and escaping with Zaecilius.
The regrouped Zealots returned to resume their attack on the now-unguarded Sanctum. However Karl Mordo had been sent to protect it. Strange attempted to trap them in the Mirror Dimension, however this enhanced their connection to the Dark Dimension, enpowering them. Mordo and Strange did their best to fight the Zealots, but were rescued by the Ancient One who teleported them away.
Kaecilius confronted his former teacher, blaming her for his actions. When she warned him that Dormamu was far more dangerous than they could imagine, the Zealots attacked her, Kaecilius stabbed her, killing one of his Zealots in the process, before escaping into the Mirror Dimension.
The Zealots next attacked the Hong Kong Sanctum, killing Wong and opening a portal to the Dark Dimension. Strange, who had been entrusted the Eye of Agamatto by the Ancient One before her death, used it to turn back time, restoring Wong and closing the portal.
Strange then entered the Dark Dimension, striking a bagain with Dormamu in which Dormamu agreed not to interfere with the Mortal Plane. As part of this bargain, Kaecilius and the surviving Zealots were transformed into Mindless Ones and dragged into the Dark Dimension.
