Bolivar Trask was an anthropologist, who saw the rise of mutants as a threat to Humanity. Bolivar was a father, his son Lawrence 'Larry' Trask, who ironically was revealed to be a mutant precognitive, Bolivar on realising this took steps to hide his genetic quirk by creating a device that 'cloaked' his genetic signature, hidden inside an Amulet that he placed around his son's neck, pledging him Never to remove it. Bolivar Also had a 'gifted' daughter, Tanya, whose ability was to travel through time, unfortunately, her control was sporadically erratic,and was lost on the temporal tides of the timestream. Tanya would be rescued by Rachel Summers in the distant future, and she became a part of the Askani under the alias Madame Sanctity. Tanya's travels through time would result in damage to Trask's property. This mysterious situation would only further cement his fearful attitude.
Bolivar decided that Humanity must take a stand against the mutants and developed a robotic solution, guardians for Humanity, that He named the Sentinels. His son Larry was 'invisible', undetected by the Sentinels' scanning devices, due to the medallion Bolivar had given him. Bolivar published articles on the threat of Mutants. One of these articles showed an illustration of Mutant overlords keeping humans as slaves. This illustration would become a symbol for human/mutant relations and several years later Quentin Quire and his Omega Gang would base their appearance on this picture.
Mayor Story Arcs
Meeting the X-men
Professor Charles Xavier invited Trask for a public debate on human/mutant relations(at the downtown television studios. Xavier's arguments that mutants were just like humans and not evil did not convince Trask (who decides to unveil his creations to the world. Trask and his scientists (when building the Sentinels' cybernetic brain), had apparently created an adaptive, open-ended tactical/strategic A.I. Cybernetics and Robotics were not his field, and was horrified when his creations rebelled and turned Against Him, claiming that they were superior to Humans. The Sentinels left the studios with Trask, returning to their 'fortress' on the orders of his first creation, the Master Mold, who orders him to construct more Sentinels.
Xavier having discovered the location of their base, with his X-Men set off to stop what trask had put into action. On arriving at the destination, the X-Men are forced into a defensive posture, after regrouping they attempt to gain entrance to the bastion, which is heavily fortified and Iceman and Beast are captured. Master Mold is intent on finding out the X-Men's secrets, and threatens Trask with the Annihilation of the nearest city and its inhabitants unless Trask lifts this information from Beast's subconscious using the Sentinel 'Psycho-Probe. During Beast's interragation, Trask discovers that the X-Men were Mutants whose primary intent was protecting Humanity and realised that he had been wrong. Grabbing the opportunity, Trask causes a chain reaction in Master Mold's power supply and heroically helps the X-Men defeat the Sentinels by sacrificing himself to destroy the Sentinel's base.
Bolivar's death would not be the end of the Sentinels though; Bolivar's son, Larry, still unaware of his own mutant status, would follow in his father's footsteps and create new Sentinels to avenge his father.
Many years later, Bolivar's nephew, Donald Trask III, would be duped by the villainess Cassandra Nova to gain control of a New type of Sentinel. The machines, now varying in size, would not harm Trask DNA. They obeyed Donald's orders (on recognition of his genetic code). However, once Nova had copied all of Donald's DNA, she disposes of him and takes over the robots.
Recently, in X-Force, Bastion who has been reactivated by the Purifiers had resurrected Bolivar Trask through use of a Technarch technology, to be part of a team of the world's foremost Mutant killers. It turned out that it was longtime X-men foe Selene that was behind these plans. Selene was eventually defeated by the combined powers of the X-men, X-Factor and the New Mutants, witch caused Bolivar and the others to once again return to death.
Age of Apocalypse (Earth-295)
In this reality, Bolivar is married to Moira MacTaggert. Together they developed the Senitnel robots, whose role is to protect the humans.
House of M (Earth-58163)
In this reality, Bolivar is the Vice President of the United States, and created the Sentinel robots to fight Magneto in a political power struggle.
Ultimate Universe (Earth-1610)
In this reality, Bolivar is named the head of the "Sentinel Initiative" in response to Magneto's attack on Washington. The Sentinel's Directive is kill any human that carries the mutant gene. When the Savage Land was discovered, Bolivar was ordered by the President to attack it, but Magneto easily reprogrammed the robots to attack humans and began in Washington again. After that, the Sentinel Initiative was shut down.
Later on, a Mark II version of the Sentinels was produced. These were SHIELD agents (60 in number) in body armor that was similar to that of the Sentinels, brandishing automatic polymer weapons.
Even later, the Sentinel program was restarted privately by the Fenris twins, using Bolivar Trask to advance them and give them the designs. When the X-men defeated the Fenris Twins and their new ally, Strye, Trask told them that a fail-safe had been activated, and he could Not stop the fleet of Sentinels. Trask promised to try to find a way because he realised that his hatred towards mutants was unfounded and wrong. The X-men left to go stop them, leaving Angel behind to make sure Trask kept his word. Trask succeeded, but only by overloading the generators in the factory. He told Angel to get out of the building, but Angel grabbed him too. Trask stuggled against Angel, wanting to die for what he had done. Angel lost his grip, and Trask fell to his death in the explosion.
Strangely enough, Peter Parker and Eddie Brock's fathers also worked for a man by the name of Bolivar Trask. He stole the idea of "the Suit" from them to be used for military applications, rather than the cancer-curing suit that the two scientists had wanted. Years after the scientists' deaths in a suspicious plane crash, Trask kidnaps Eddie in an attempt to steal the suit from him. Beetle breaks Eddie free, and he escapes from Trasks labs. This is probably not the same man who developed the Sentinels; he has a different appearance and personality and is alive after the first Trask died.
A former member of S.H.I.E.L.D., Trask left the organization, feeling it didn't do enough, particularly in the case of the rising Mutant population. Believing that Mutants were a threat to humanity's very biological existence, Trask began the Sentinel program, building a machine that could fight and eliminate Mutants. His forces kidnapped Wolverine and tested the first Sentinel on him. The Sentinel later took on the entire X-Men team, at first fighting them in Trask's underground facility, then above ground, after Magneto caused the Secret base to be known to the public, rising to the surface in the middle of downtown Bayville, exposing both the Mutants to the world and Trask's activities to the authorities. Trask was imprisoned.
Later, when Apocalypse began his plot by erecting force fields around various pyramids throughout the world, S.H.I.E.L.D. released Trask against the doubts of Nick Fury, believing that Trask's Sentinels would be valuable against Apocalypse, himself an advanced Mutant.
Wolverine and the X-Men
As Senator Kelly treated the mutants as a danger to Humanity, Bolivar created the Project Sentinel which aimed to terminate unregistered Mutants. The first mutant to be detected by these robots was Rogue who was later saved by her co-X-Men members. Senator Kelly was then abducted by Quicksilver and was taken to Genosha. This scenario gave the chance for Mystique to take over Kelly's position while she was in disguise. She told Trask to create a set of Sentinels to fight the Mutants. Trask created 15 but Mystique asked for more because she wanted to cause war between the Humans and the Mutants.