Notes: As originally conceived, Xorn was simply Magneto infiltrating the X-Men. A later retcon cast him into the role of an insane mutant pretending to be Magneto who was in turn pretending to be Xorn.
Annual 2001 - 'The Man from Room X!' Omnibus (2nd Edition) - 'New X-Men Omnibus' #122 - 'Imperial' #124 - 'Superdestroyer' #125 - 'Losers' #126 - 'All Hell' #127 - 'Of Living and Dying' #135 - 'Teaching Children About Fractals' #136 - 'When X Is Not X' #137 - 'Riot at Xavier's' #138 - 'The Prime of Miss Emma Frost' #139 - 'Shattered' #140 - 'Murder at the Mansion' #141 - 'Whodunit?' #146 - 'X-Men Emergency!' #150 - 'Phoenix Invictus'