Kevin Sydney (as the Changeling) originally works for the villainous organization Factor Three. He acts as the Mutant Master's second-in-command in an effort to trigger World War Three. He captures the heroic X-Men, The Mutant Master is exposed as an extraterrestrial and goes out of control. The mutants of Factor Three team with the X-Men to defeat the Mutant Master.Following that group's defeat he reforms and, unbeknownst to the X-Men, is recruited by Professor X to replace him. The Professor desires to isolate himself to prepare for a defense against the alien Z'Nox invasion. The Changeling, masquerading as Professor X, led the X-Men's efforts to defeat the Subterranean Grotesk. He is then mortally wounded in battle with Grotesk by the exploding of an oscillotron machine. He dies preventing the destruction of Earth. However, the X-Men thought it was actually Professor X who had died and did not find out until later that it was in fact Changeling.Although dead, Excalibur encounters what they thought was his malevolent ghost, however, it turns out to be a hoax perpetrated by Merlyn, with Merlyn posing as Changeling. Changeling did return and battle She-Hulk when he was raised from the dead as a zombie by Black Talon to form part of the team X-Humed. It is Changeling who is able to break Talon's control of him long enough to allow She-Hulk to win and lay the zombies back to rest. Show less «