Mister X is a mutant who was born in to a wealthy family and had a normal childhood, until he saw a woman die on the street. He then became fascinated with death. The experience triggered his telepathy which formed a bond with the dying woman. He spent many years trying to recreate the thrill of seeing something die. He finally experienced death again sometime later when he placed his dog into an oven and watched it die. His parents were in shock after seeing what a young Mister X did to their dog. Mister X then killed his parents and dedicated his life to the art of killing.
Mayor Story Arcs
He decided to dedicate his life to murdering people and to do so he trained and studied with various combat teachers all around the world. After he'd master a certain combat style or skill, he'd kill his masters and then scar himself in a ritual fashion for each life he took. He destroyed every record of his life and he then focused on killing fighters who claim to be the best. He eventually learned of Wolverine and he defeated him himself. He achieved the title of "The Best There Is". He then asked Wolverine to join him on his mission but Wolverine declined and became enraged. The two squared off again but the fight was interrupted by X's bodyguard, Blok. X then released Wolverine as he thought the fight was won unfairly. And he promised him a rematch.
Their rematch came a few weeks after, both entered the Bloodsport tournament in Madripoor. Before he fought Wolverine, X humiliated Taskmaster, who was one of the best fighters in the tournament. Mister X and Wolverine then met in the championship but Wolverine realized that X was using his telepathy to his advantage in order to anticipate his moves. Wolverine then lost his mind and went on a berserker rage and X then loss the fight but was saved once again by Blok.
In the Wolverine:Mister X one-shot he is determined to avenge his defeat at the hands of Wolverine. He goes so far as to train with bears to simulate Wolverine's berzerker tendencies in battle. After feeling he is ready he holds a kindergarten class hostage and mails Wolverine's the teacher's head to lay down his challenge. The two meet in the weapons hall of a museum and begin their fight. Mister X holds the upper hand for much of the fight until Logan realizes he is being goaded into going feral. Wolverine then stops fighting and rebutes Mister X's threats against him and any other children. Distraught, Mister X then receives a call to join Norman Osborn's team of Thunderbolts.
Norman Osborn's new team of Thunderbolts are sent on a mission in Madripoor in order to recruit Mister X. Black Widow II (Yelena Belova) mentions that Mister X is the reigning champion of the annual Bloodsport fighting tournament held in Madripoor. It is also mentioned that he has termination warrants out on him in seventeen countries around the world. Mister X would be attending the opening of a new opera house with the ruler of Madripoor, Tyger Tiger. The Thunderbolts planned to go in disguise as performers in the show. Mister X finally arrives in the opera house and talks to Tyger Tiger about how the people love their champion more than their ruler. He also tells her about a rumor of an assassination attempt later that evening. The two watch the show as Black Widow II and Paladin were performing on stage. Weapons then fell from an opening in the ceiling and the "performers" kill the guards. People flee and Tyger Tiger tells Mister X to come with her but he refuses as he wants to fight. He gets threatened by the Thunderbolts but he easily dispatches of Paladin and Black Widow II. The whole opera was then cleared and Mister X stopped acting as if they were really fighting. Ghost then sends in a body that looked like Mister X's to let the people think he was killed. They then burn down the opera house as well. Mister X then gets welcomed to the Thunderbolts. They ask Mister X why he's in the team even though he's already a rich man. He answers that he's in because he's bored and he wants to find an opponent who is a challenge to him. And if they can't find someone that can match him and his skills, he'd just have to settle to killing the rest of the Thunderbolts. Since then, he has been at conflict with his fellow teammates, especially Headsman. He angered Headsman and lured him into a fight, where he easily defeated Headsman. Mr. X then helped the team in attempting to capture Black Widow, who turned out to be Natalia, Songbird and Nick Fury. Mr. X fights Black Widow and Songbird in a forest, easily defeating both of them. However, Songbird saves them and they make an escape. Mr. X also helped the team capture Iron Fist. However, Luke Cage later rescued Iron Fist and knocked out Mr. X in the process. Later, during the Siege of Asgard, Mister X and the Thunderbolts fought the Mighty Avengers, where X's powers were outsmarted by Amadeus Cho, and, after briefly taking possession of the Spear of Odin, defeated outright by Quicksilver's super speed. He was presumably apprehended along with the rest of the Thunderbolts team minus Paladin and Ant-Man once the Siege ended.
Powers & Abilities
Mister X is a low-level psychic. He can easily predict the moves of his opponents which gives him an advantage in hand-to-hand combat. Mister X is a master of every martial art known to man and has even attempted to create his own. He is highly efficient in using swords and many other weapons. He's a murdering sociopath who savors the death of other people at his own hands.