History
Vulcan's mother and father were kidnapped by the Shi'ar, and he was kept alive to be a slave. He used his powers to escape and come back to Earth, where he was discovered by Moira Kinross, and he joined a team of other mutants to train. Fighting on Krakoa, he "found the X-Men dead": In fact, he accidentally killed Jean Grey while attacking Krakoa, killing Havok in an attempt to calm him down, and then killing Angel, Iceman, and Polaris so they wouldn't say anything.
He then became the leader of the X-Men, trying to make amends for his crimes, but without ever telling the truth to his teammates.
He later learned that Krakoa had been brought back to Earth by the Silver Surfer. He became defensive when asked about it, showing that something bad had happened. He then tried to kill the X-Men, but Darwin took away the knowledge of his power while Sway stopped time. Charles Xavier then saw everyone he killed.
He announced to the public that he was going into outer space to fight the Shi'ar, in order to protect another planet, but was in fact exiled, stuck in a dome on Krakoa out in space, and stayed there at least for 5 years and 3 months. In order to get food, he had to put his hand on a sensor, which replayed the events on Krakoa.[1]