In Thanos' invasion, Dr Strange used the Darkhold to dreamwalk through the Multiverse in search of a possible solution to the conflict. This led to the destruction of an entire reality due to an Incursion. With Thanos already dead, Strange confessed to the rest of the Illuminati that he had destroyed a reality by asking the rest of the team to kill him to protect the Multiverse. Due to Strange's death, the mantle of Sorcerer Supreme was given to Mordo, he joined the Illuminati. He has a sword.