History
Charles Xavier was the leader and founder of X-Men, and the builder of the Danger Room.
When his creation was upgraded with Shi'ar technology, Danger was born from it and asked him where was she. As Xavier denied to answer and faked to be unaware from it, Danger eventually rebelled against the X-Men and called out to robotic creations. Her call was heard by both Ultron and his son Victor Mancha.
Ultron came to Westchester and killed almost all the students, causing Xavier to collapse. After having killed the remaining X-Men, Danger and Ultron had as a gift from their children the Wild Sentinel Charles Xavier, who had recovered from his psychic trauma.
He tried to explain his acts and to apologize, knowing he wouldn't get any forgiveness. Ultron then made the Wild Sentinel close, crushing Xavier in it.[1]