BIOGRAPHY page 1
The being known as Gamesmaster is a self-styled “omnipath,” an individual with hyper-telepathy which mentally links him with everyone on the planet. Unfortunately for him, the Gamesmaster lacks the ability to shut these thoughts out, resulting in him constantly experiencing the loves, hates and desires of the planet’s billions of humans. His single, burning motivation is to find whatever distraction he can manage as not to be overwhelmed by humanity’s constant torrent of emotions.
Beyond this, almost nothing is known about the Gamesmaster’s background. Given that he has never appeared in person to those with whom he has conversed, instead appearing as a telepathically generated avatar, everything about his appearance is likewise a possible lie. As such, characteristics such as his appearance, age, ethnicity and even gender is questionable.
At some point, the Gamesmaster encountered Selene, the reigning Black Queen of the Hellfire Club. Together, they hatched a mutually beneficial plan, the creation of a group of mutants called 
the Upstarts, each of whom would compete against each other for “points” by killing other mutants. For Selene, this allowed her to direct others to do her dirty work, killing those who opposed her and getting her closer to seizing control of the Hellfire Club. For the Gamesmaster, it provided a much needed distraction. Somewhere along the way, the Gamesmaster had discovered that his observation of competition between others could provide a respite from his “condition.” By focusing in on these competing egos, and manipulating them along the way, the Gamesmaster could temporarily shut out the minds of billions of others with whom he was constantly, telepathically connected. [Uncanny X-Men (1st series) #283, Stryfe's Strike File #1]
The exact circumstances of the Upstarts' formation is unknown, but it seems each of these mutants were initially unaware of Selene’s connection to their group and all firmly believed that they had asked the Gamesmaster to arbitrate their contest. The point of the Upstarts competition (besides boredom and "kicks" for the participants) was also ambiguous. Some sources indicated the winning Upstart would gain control of all the assets of the losing players. Other claims indicated a larger prize like immortality or ultimate power. It's not unreasonable to assume Gamesmaster used telepathic manipulation to keep the Upstarts in the dark about their fraternity's origins and motivations.
This manipulation was also likely apparent when the Gamesmaster informed the group of their fourth member, the mutant-hating and very human Graydon Creed. At first, mutant supremacist Fabian Cortez was incensed that a mere human could be considered a member of the group, though he quickly relented. The trio likewise conceded to the Gamesmaster when he announced the inclusion of a fifth and final member of their group, despite the addition of more contestants dividing their attention. [Uncanny X-Men (1st series) #299]
As the Upstarts embarked on their various assignments, the Gamesmaster monitored them all and observed. He watched as Fabian Cortez manipulated the Acolytes, a group of mutants dedicated to the teachings of Magneto, all to get close to the master of magnetism… just so Cortez could orchestrate his death. Indeed, Gamesmaster awarded an unspecified, large number of points to Cortez for this kill, putting him in the lead of the competition and thus their current “leader.” However, Gamesmaster reveled in the intra-chaos of the Upstarts as well as the violence against their targets. Knowing that the Acolyte known as Neophyte was in earshot, Gamesmaster 
manipulated Cortez into confessing his part in betraying Magneto, shattering Neophyte’s allegiance and ultimately leading to Cortez’s defeat at the hands of the X-Men. The Gamesmaster later gleefully informed Cortez that he had not only failed to kill Bishop as he had believed during his battle with the X-Men, but revealed that he was to be stripped of all of his points earned to date, implying that Magneto was not dead after all. [Uncanny X-Men (1st series) #299-300]
The fifth and final member of the Upstarts was Siena Blaze. Originally, Trevor Fitzroy had intended to propose her invitation, but the Gamesmaster had beaten him to the punch, 
presumably already aware of Fitzroy’s suggestion as soon as he had thought it. The Gamesmaster watched as Siena, in her first outing, used her incredibly powerful electromagnetic powers to down the X-Men’s Blackbird aircraft, intending to kill its passengers, Cyclops, Storm and Professor X. Shortly after her attempt, however, the Gamesmaster delivered the news to her that the X-Men survived. [X-Men Unlimited (1st series) #1]
As distracting as the Upstarts competition was, it was not enough for the Gamesmaster’s needs, so he also took an interest in the plots of others. One of these were the machinations of Matsu'o Tsurayaba, who was planning to kill Psylocke – an X-Man whom Shinobi Shaw had plans for himself. Despite his objections to someone not in their competition having such a right, Shinobi abided by the decision of the Upstarts’ arbiter and obeyed the Gamesmaster’s decision. [X-Men (2nd series) #22]
According to the rules of the game, the member with the most points was effectively the leader (or “czar”) and had the right to petition an audience with the Gamesmaster, or call a meeting of all of the members. Although not in the lead, Fitzroy gained the attention of the Gamesmaster by capturing and torturing Selene, impressing the omnipath enough to use his ability to connect all five members’ mind on a psychic plane. After officially introducing them to Siena Blaze as their newest member, the Gamesmaster tallied each member’s current scores and then informed them of their next target – the mutant inventor known as Forge. The Gamesmaster informed them that, in the next twenty-four hours, Forge would do something that would directly affect the fate of every mutant on the planet – unless he met an untimely demise. Fitzroy was given the chance to attack first, but failed in his attempt. Oddly, the Gamesmaster did not attempt to send any other member to finish the job, nor did Forge end up inventing anything of significance in the time frame the omnipath stated. [Uncanny X-Men (1st series) #301]
Continuing his side deals, the Gamesmaster began striking bargains with other nefarious parties, such as the deadly Mr. Sinister. The master geneticist desired the DNA of Proteus, the deceased 
son of Moira MacTaggert and one of the most powerful mutants to have lived. Gamesmaster was perfectly happy to use members of the Upstarts to assist. Offering her a chance to get ahead of the other Upstarts, the Gamesmaster tasked Siena Blaze with recovering computer records of Proteus’ DNA sequence from Moira’s computer files on Muir Island. He also ordered her to kill Moira as well. Although she was only a human, the Gamesmaster assured Siena that he would award her points for killing a “potential mutant.”
The fact that Siena's quest on Muir Island was not completed was of no consequence to the Gamesmaster, for when the empty-handed Siena returned to the Gamesmaster's lair, he declared that the players were on their own once his rules had been stated. Fortunately for Siena, she did return with something Sinister found useful – under her fingernails was the DNA of Rachel Summers, which Sinister believed was a worthy secondary objective. The Gamesmaster seemed not to care either way. [Excalibur (1st series) #72-74]
In addition to their numerous defeats, the participants among the Upstarts decreased when Fabian Cortez was killed and taken out of the game. In the midst of this lull, the Gamesmaster appeared before a drunken Shinobi Shaw and warned him that if he didn't become proactive with his killing of notable mutants, he would lose all the points he had so far collected. Shinobi did not feel it was the Gamesmaster's place as arbiter to interfere in this manner but he nevertheless did heed his suggestion when the Gamesmaster suggested a vassal, the New Warrior known as Justice. What Shinobi did not know, as the Gamesmaster was presumably already aware, was that Night Thrasher, leader of the New Warriors, intended to use Justice to infiltrate the Upstarts. [New Warriors (1st series) #43]
Sensing the interest of its members was waning, the Gamesmaster once again took a proactive stance with the Upstarts and essentially forced them into a game he called the “Younghunt.” In this phase of the game, the targets were the surviving members of the New Mutants and Hellions. Siena Blaze, Graydon Creed, Shinobi Shaw and Trevor Fitzroy were tapped to participate in the hunt. Some were somewhat annoyed about having to turn their attention to this new game, but were encouraged to participate when the Gamesmaster revealed that both Siena Blaze and the Fenris twins, the latter of whom not being official members of the Upstarts, had already started the game and had captured three former New Mutants.
The Upstarts scored some early successes and the Gamesmaster kept those that the Upstarts captured in the psychic landscape known as the “Mindstream,” a place where he was forced by 
his condition to spend most of his time. It was from there that the Gamesmaster watched as Shinobi Shaw explained to Justice his plan to disrupt the rules of the game to ensure he won it – by eliminating not only his fellow Upstarts but the Gamesmaster himself. Despite his efforts to use telepathic screens to keep the omnipath from learning of his plans, the Gamesmaster was well aware of Shinobi’s intentions and anticipated the coming betrayal.
Although the Gamesmaster was well prepared against those who would move against him, the Upstarts themselves were not. Once X-Force and the New Warriors began to move against the Upstarts, they fell one-by-one, each giving up the others to save their own skins. The trail eventually led to Shinobi’s chalet in the Swiss Alps, where the Gamesmaster was physically keeping the captured mutants. As the two teams of heroes approached the chalet, the Gamesmaster demonstrated that his omnipathy included control as well as communication. Taking mental control of the captives, he used them to fight their rescuers. Indeed, the battle did not last long and the thralls of the Gamesmaster prevailed, after which he declared his “Younghunt” over.
As he contemplated what to do with his prizes, the Gamesmaster was pleasantly surprised by the arrival of Cannonball's sister, Paige, as his omnipathy had not detected her presence due to her 
“Husking” powers. He was further intrigued when she suggested a new game to him – a race to see who would lead the next generation of mutants – Xavier, the Acolytes or anyone else. The Gamesmaster was impressed with this suggestion and declared Paige Guthrie the winner in their little encounter. As his telepathic avatar departed, Cannonball and the other former captives found themselves freed. Although grateful at her quick thinking, they wondered whether Paige's deal with the Gamesmaster sealed the future for the next generation of mutants. [Child's Play crossover]
[Note: It was at this point that a man in his 30s or 40s was depicted in the flesh, heavily 
implied to have been the Gamesmaster’s true form. Although many of his features were different (hair and glasses), the eyes and jawline of this man definitely bore a resemblance to the Gamesmaster and his dialogue spoken to himself was definitely meant to convey that it was him. This character has yet to have appear since.]