The original Mk I Sentinels had been created by anti-mutant bigot Bolivar Trask, who came to understand that not all mutants were a threat to humanity and ultimately died to stop his own creations. However, Trask's son Larry, erroneously blamed the X-Men for his father's death, and decided to create new Sentinels to track and imprison the X-Men and other mutants.
Thus, Larry developed more advanced Sentinels, some according to his own designs and some using his father's designs as a base (the 'leader' of the Mk II Sentinels, Number Two, was built from Bolivar's designs). Larry's main improvement was the addition of technology that allowed the Sentinels to physically adapt to any threat.
Larry always wore a medallion that had been given to him by his father to cloak his own mutant powers, preventing his Mk II Sentinels from turning on him. Unfortunately, when the Sentinels eventually engaged the X-Men, the medallion fell from Larry's neck and the Sentinels discovered that he was a mutant. Deciding they would not obey a mutant, the Sentinels captured Larry, freeing themselves from his control.
After the X-Men destroyed some of the Sentinels, the X-Man Cyclops convinced the Sentinels that they should seek out and destroy the main cause of human mutation instead of mutants themselves. Fooled by Cyclops' logic, Number Two took the surviving Sentinels directly to the main source of mutagenic radiation on Earth: the Sun.
While orbiting the sun, Number Two computed that they lacked the firepower to destroy it and the Sentinels decided to approach the problem differently. They returned to Earth with a new goal: Try to provoke and control sun radiation, creating a sun-flare that would sterilize mankind, preventing the birth of new mutants (and humans). The Sentinels would then create a new species that could not mutate.
However, the extended period spent in orbit of the sun actually caused mutations in Number Two, including the will to kill humans to reach their goals. On this occasion, the Avengers fought the Mk II Sentinels and destroyed them. Larry Trask also died in this operation when one of his depowered Sentinels collapsed on top of him, crushing him beneath its bulk.
- Adaptability: A Mark II Sentinel could analyze superhuman powers and weapons used against it and, in a matter of seconds, develop specific ways to counteract them. This information was then communicated to all the other Sentinels. Developed counter-powers include:
- Energy Blast: The Mark IIs could offensively project a variety of different energy from their palms, including but not limited to: Plasma, electrons, stun beams and heat. They were also armed with a disintegrator that only worked on inorganic matter.
- Flight: Using jets built into their feet, the Sentinels are capable of flight.
- Mutant Detection: The Sentinels constantly scanned all the living beings in the immediate surrounding area and were able to determine if they were humans or mutants. The range was slightly increased from the Sentinels Mk I.
- Remote Control: The Mark II Sentinels could be controlled by a human wearing a specific cybernetic helmet. This control decreased the fighting abilities of the Sentinels. Mutants have been proven unable to use the helmet, although a mutant telepath can mind-control a human to use it.
- Robot: Due to its nature, the sentinels were protected by the sheer strength of their skin. They could not be affected by emotional or mental attacks, nor by illusions. However, they were susceptible to attacks affecting machinery.
- Self-repair: The Mark II could repair damage to itself in seconds.
- Teleportation: Mark II Sentinels could create teleportation gateways. This ability has only been used by the mutant Number Two, and so may be a unique mutation.
- Unlike their predecessors, the Mk II Sentinels were programmed to protect mankind, no matter the cost. Although they could kill mutants, they could never damage or kill a human. However Number Two and other mutant Mk II Sentinels were able to override this programming.
- 14 appearance(s) of Sentinel MK II
- 1 appearance(s) in handbook(s) of Sentinel MK II
- 4 minor appearance(s) of Sentinel MK II
- 3 mention(s) of Sentinel MK II
- 6 image(s) of Sentinel MK II