1980sThe character first appears in the title Uncanny X-Men, and is briefly mentioned during the Mutant Massacre crossover by Sabretooth as being the leader of the Marauders and who sent them to slaughter the Morlock population; and in the following issue, the X-Men member Psylocke picks up a shadowy mental image of the Marauders' Master from Sabretooth's mind. After appearing on-panel in issue #221 (Sept. 1987), Mister Sinister plays a major role in the Inferno crossover, revealing to have cloned Madelyne Pryor from Jean Grey, with the purpose of her to mate with Cyclops and produce a child, their son Nathan; and also having manipulated Cyclops' life since early childhood. After a battle with the X-Men and X-Factor, the villain is apparently destroyed by Cyclops' optic beam.Classic X-Men #41 - 42 (Dec. 1989) details the role Mister Sinister played in Cyclops' life at the orphanage in Nebraska. The story features a boy named Nathan who is obsessively fixated on Cyclops - and whom Claremont intended to actually be Mister Sinister. However as Claremont left the X-Men comics, this origin was never picked up.1990sMister Sinister returns in the title X-Factor, leading the Nasty Boys and allied with the mutant terrorist Stryfe. The character features in the X-Cutioner's Song crossover, impersonating Apocalypse and commanding his Four Horsemen to capture Cyclops and Jean Grey. Sinister hands them over to Stryfe in exchange for a canister containing his genetic material, but Sinister finds it empty. The character afterwards confronts Cyclops and reveals that it contained the Legacy Virus.The character's origin story is told in the limited series, The Further Adventures of Cyclops and Phoenix, and is established as Nathaniel Essex, a scientist from the 19th century obsessed with evolution. Essex makes a pact with the ancient mutant Apocalypse who transforms him into a virtually immortal being. It is furthermore established that Mister Sinister created Cyclops' son Nathan - who became the time-traveling soldier Cable - to destroy Apocalypse.2000sMister Sinister appears in the title Gambit and a connection between the character and the X-Men member Gambit is revealed. The character attempts to use the High Evolutionary's space station to mutate the human population but is stopped by the X-Men. The character also appears in the alternate universe title Mutant X. In the series Weapon X, Mister Sinister experiments on mutants under the guise of Dr. Robert Windsor; issue #14 reveals that the character worked alongside the Nazis during World War II. The character also appears in the non-canon miniseries, X-Men: The End and the limited series X-Men: Colossus - Bloodline.Mister Sinister reappears in X-Men: Endangered Species crossover, sending the Marauders and Acolytes out to murder all those who have knowledge of the future; In the Messiah Complex crossover, Sinister seeks out the first mutant child born since Decimation. However, the character is killed by Mystique who presses his face onto an unconscious Rogue. Show less «