Mairsil

Mairsil, known as the Pretender, was a power-hungry wizard, who was a member of the Conclave of Mages during the post-Brothers' War Dark Age of Dominaria.

History
Lord Ith was the ruler of the Conclave until Mairsil usurped his power and imprisoned him below the Conclave's citadel, installing himself as the First Among the Equals.

Ith's cage was created by Barl. It was made of watersilver and hung directly over a bottomless pit, siphoning off his mana and driving him mad. If Lord Ith hadn't managed to summon a Rag Man, the cage would have killed him. The Rag Man eventually led the powerful young wizard Jodah to Ith, who could free him. Ith was almost completely mad by that point, and destroyed both Mairsil and the Conclave before Jodah was able to cure his mind.

However, Mairsil had imbued his life into a small ruby ring, and his essence survived for the next 2,000 years. The artifact was found during the Ice Age by a soldier named Lim-Dûl, who gained vast necromantic abilities thanks to the power of the ring. In the service of Leshrac, he terrorized Ice Age Terisiare with undead hordes until being defeated by an alliance between Kjeldor and Balduvia.

Because Jodah was magically still alive, the spirit of Mairsil attempted to take control of Lim-Dul so that he could use the necromancer's powers against his archenemy. Before this was possible, Leshrac, seeking extra power himself, cut off the necromancer's hand with the ring. The Pretender was plunged into darkness once more.

The ring's final wearer was a task mage named Jaya Ballard — Jodah's trusted confidant. Mairsil spent the next decade poisoning her mind, eventually willing her to betray her master and slit his throat. But Jodah fought back, managing to ignite Jaya's planeswalker's spark with his magical mirror. Jaya's ascension, and the energies it released, destroyed the ring and eradicated all traces of Mairsil's soul.