While X-Men comics may be full of colorful and over-the-top supervillains, the Sentinels are a mainstay antagonist with a different appeal. They are the embodiment of the human fear that a singularity will bring about an artificial consciousness, which will in turn decide that we need to be saved from ourselves. These purple and pink goliaths have been an integral part of X-Men lore since the earliest days of the Children of the Atom and they have played a part in almost every X-Men story that takes place in an alternate future timeline.

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Being such an X-Universe staple, there have been more than few different iterations of these mechanical monstrosities, and we’ve put together a ranked list of the 15 coolest, deadliest, and most essential Sentinels that have ever appeared in the comics.

15 MK I SENTINELS

MK I Sentinel

Just a little more than a dozen issues into their initial run, the X-Men came into contact with the robot mutant-hunters known as Sentinels. These cybernetic marvels were created by Dr. Bolivar Trask in “X-Men” #14 (1965). In this issue, Stan Lee is credited under the title Doctor of Story, Jack Kirby as the Dean of Layout, and Jay Gavin as Master of Art. In other words, Stan "The Man" came up with the concept for the Sentinels, while King Kirby and Gavin are responsible for the look.

The story here concerns a press conference given by Dr. Trask in which he declares mutants a hidden menace. When Professor X sees a newspaper article detailing Trask’s allegations, he knows this paranoia is a greater threat than any villain the youngsters have faced. Long story short, Xavier organizes a televised debate with Trask to dispute his claims, but Trask brings along some friends… the Sentinels. The anthropologist had created the massive ‘bots to save humanity, but they quickly decided the best way to do that was to control humans. Once he had seen them in action, Prof X notes: “They’re perfectly disciplined -- completely emotionless! And yet, they’re more than mere robots!”

14 SENTINEL FORCE

Sentinel Force

Marvel made its first serious foray into the world of manga with the “Marvel Mangaverse: New Dawn” and the “Marvel Mangaverse: X-Men” oneshots in 2002. Designated Earth-2301, Marvel revisited this parallel universe the following year in the “X-Men: Ronin” 5-issue miniseries. The wildly different version of the X-Men included ninja clans, skimpy skirts, Cyclops in a mech suit and Toad as an old master. What we are concerned with here, though, are manga style Sentinels.

In this reality, it is a police chief who leads mutant witch hunts. His name is Shigen Yoshida and he organizes an anti-mutant division of his Police Force called the Sentinel Force. The squad is made up of five specially-selected recruits that pilot Sentinel mechs. Forge of this Earth was one of these pilots. When the Sentinels are sent to take down the X-Men, the whole team is slaughtered. That doesn’t stop Yoshida, though; he arranges to have the mechs reconstructed and new pilots trained with the financial backing of the Hellfire Club.

13 SENTINEL SQUAD O*N*E

Sentinel Squad O_N_E

The Sentinel Squad O*N*E is the brainchild of Dr. Valerie Cooper, a security advisor to the president with an anti-superhuman stance. The concept of the initiative was to have soldiers pilot Sentinel armors, much like the Mangaverse’s Sentinel Force. The O*N*E models first show up in the “Decimation: House of M - The Day After” oneshot (2006) written by Chris Claremont. They were created by the armor master himself, Tony Stark, and his righthand man Rhodey served as a O*N*E instructor and commanding officer.

After the events of M-Day decimated the mutant population, the Office of National Emergency sent Sentinel Squad O*N*E to the Xavier Institute under the guise of protecting the remaining mutants at the school. However, the real reason was that O*N*E’s deputy director General Demetrius Lazer wanted the mutants at the school contained and monitored closely. Though the bigger-than-usual Sentinels initially meet resistance, an uneasy truce is established with the X-Men.

12 EARTH-889 SENTINELS

Earth-889 Sentinels

Parallel universe specialist Warren Ellis and acclaimed artist Adi Granov introduced the steampunk X-Men of Earth-889 in “Astonishing X-Men: Ghost Boxes” #1 (2008). This version of the mutant superheroes are called X Society and operate out of New Portsmouth Bay in the State of New Albion. The team includes “the most famous adventurer in the civilized world,” Scott Summers, as well as Miss Emma Frost, Dr. McCoy and the goggle-wearing Mister Logan.

When they assist an inspector of the Western Yard in tracking down a “homo mutandis” murderer, things go awry and the X Society is blamed for an aerodrome accident in which many innocents perish. This prompts the government to put them on house arrest and station this reality’s Sentinels around Emma’s estate. Earth-889 was pre-digital, so these anti-mutant machines were mechanical rather electronic. Emma refers to them as a “clockwork firing squad.” This take on the Sentinels makes our list for having the most divergent look.

11 PUTERNICSTAN SENTINELS

An image Puternicstan Sentinels from the X-Men comics

Puternicstan was a contested land between Symkaria and Latveria that made its first appearance in “X-Men” #20 (2011). Having been caught in the middle of the two warring nations, its people desired independence and were willing to go to extremes to secure it. A Puternicstanian official -- simply going by the Governor -- organized the acquisition of three Sentinels off the black market in the hopes of getting at least one good “brain.”

She had secretly amassed an army of “brainless” Sentinels that had been modified so they could be slaved to a single functional Sentinel. These Purple’N Pinks were also modified so they could be sent after any target, not just mutants. It turns out the Governor did not want them to hunt mutants, but instead to bring war to her Symkarian neighbors. The combined might of the X-Men and War Machine fail to bring the army of Sentinels down and a deactivation code found at the last minute is the only thing that saves the region from another war.

10 WILD SENTINELS

Wild Sentinels

In “New X-Men” #114 (2001), writer Grant Morrison revealed that the U.S. had secretly funded a shadow Sentinel program in Ecuador during a Civil War. The installation was “a basic Master Mold factory unit,” but one designed to adapt to its environment by utilizing any raw materials or technology in its test radius to make new Sentinels. While the project was abandoned, the Master Mold continued along as per its programming, pumping out new 'bots.

X-Men villain Cassandra Nova brought Dr. Bolivar Trask’s nephew, Donald Trask III, to the site knowing that the Sentinels would recognize and obey a Trask. Cassandra had Donald command the Master Mold to construct four massive Wild Sentinels and task them with exterminating Genosha’s population. The x-gene hunting androids annihilated upwards of 16.5 million mutants on the island in a brutal, Godzilla-esque attack. One of the monstrosities was eventually converted into a memorial for the believed-dead Magneto.

9 DANGER ROOM SENTINELS

Danger Room Sentinels

While the Danger Room could be set to replicate any threat the X-Men might need to prepare for, a regular opponent in the training room was Sentinels. Since the giant ‘bots proved to be a near constant threat to mutants, this makes perfect sense. In “Uncanny X-Men” #444 (2004), lauded X-Men writer Chris Claremont and fan-favourite artist Alan Davis gave us a story that started with Wolverine, Storm and Nightcrawler fighting against a wave of Sentinels in the Danger Room.

Rogue had brought in a group of new students to train, but when she realized her teammates were having a session, she figured it was a good chance for them to see some real X-Men in action. She commented to the youngsters that “Ev’rything y’all want t’know ‘bout the danger Room, an being’ an X-Man is right b’fore your eyes.” The contingent of Sentinels the trio were skirmishing with consisted of the multi-storey tall classic variety, but also smaller insectoid models that resembled ants, centipedes and flies. These ones were a tribute to the Wild Sentinels from Grant Morrison's acclaimed "New X-Men" run.

8 MASTER MOLD

Master Mold

Just like the original MK I’s, Master Mold was a Dr. Bolivar Trask creation. In real life, of course, Stan Lee and Jack Kirby came up with the characters. While the Sentinels first appeared in “X-Men” #14 (1965), this one-of-a-kind robot's existence was not revealed until the next issue. It was a gargantuan Sentinel that could manufacture MK I’s and design new models. What Trask did not expect is that Master Mold would take control of the Sentinels. Upon assessing the situation, it determined humans needed to be ruled, to be protected.

It wanted the anti-mutant leader to help it create a thousand Sentinels so it could achieve its programming to eradicate mutants. Master Mold was not above threats, though, and when Trask tried to refuse, it said it would disintegrate a nearby town. Realizing that he was responsible for a danger greater than mutants, he sabotaged a piece of equipment, which lead to an explosion that levelled the lab. Being more of a system than just a nuts-and-bolts robot, Master Mold comes back to hunt mutants numerous times after his supposed defeat at the hands of its maker.

7 NIMROD

Nimrod

In the X-Men’s first alternate future timeline adventure, “Days of Future Past,” the assassination of Senator Robert Kelly leads to strong anti-mutant sentiment in the U.S. Eventually, laws are passed to diminish mutant rights and the government even reinitiates the Sentinel program. As usual, the lumbering giants quickly decide that protecting humans means ruling them, and within a short time, they control all of North America. They start by eliminating not only masses of mutants, but other powered individuals as well. Any survivors end up in internment camps.

In this dystopian future, Cyberobotics had developed a highly advanced Sentinel called a Nimrod. The pink powerhouse was activated by an energy pulse emitted when Rachel Summers travelled back in time in “Excalibur” #66 (1993). Kate Pryde managed to blow up the Cyberobotics facility as planned, but not before Nimrod was transported through time himself. However, he actually first appeared in “Uncanny X-Men” #191 (1984) and his activation happened off panel in “Uncanny X-Men” #192.

6 BASTION

Bastion

Being a next generation Sentinel from the future that fights crime in the past was just the beginning for Nimrod. When it came across a component of the seemingly destroyed Master Mold in “Uncanny X-Men” #246, the two merged and rebuilt themselves. In the next issue, this mash-up of Sentinel technologies from different eras engaged in a pitched battle with the X-Men, which at this point included Allison Blaire, aka Dazzler.

Blaire was in possession of the pan-dimensional portal known as the Siege Perilous and the X-Men used it to trap the Nimrod/Master Mold construct. While that seems like a fitting end to a bizarre story, this entity was not so easily extinguished. It reemerged from the Siege Perilous as a unified being that appeared human and went by the name Bastion. He was still a Sentinel at his core, though, and his primary programming led him to set the mutant-culling Operation: Zero Tolerance plan into motion. This program created the Prime Sentinels. Speaking of whom...

5 PRIME SENTINELS

Prime Sentinels

The Sentinels were back in a major way when the robot menace known as Bastion started an anti-mutant program codenamed Operation: Zero Tolerance in "X-Men" #65 (1997). The agenda was to morph humans into cyborgs called Prime Sentinels and reinsert them back into society as sleeper agents. Many were tricked by Bastion’s Prospero Clinic, which offered “miracle cures,” but actually outfitted patients with cybernetics like the classic Sentinel hand blasters, lifeforms sensors and cloaking devices.

To give you an idea of their power and efficiency, these new age mutant-hunters managed to neutralize Storm, Cannonball, Cyclops, Wolverine and Jean Grey in four coordinated assaults. Bastion and the Primes even captured Professor X and kept him imprisoned at their New Mexico headquarters. Further, the X-Men weren’t able to stop these hybrids without S.H.I.E.L.D. stepping in and commanding Bastion to stand down. The agency revoked Operation: Zero Tolerance’s rights and privileges, which had regrettably been government-backed. As with any well received X-villains, this was not the end for the Prime Sentinels.

4 ULTIMATE SENTINELS

Ultimate Sentinels

Bolivar Trask also developed the original Sentinels in the Ultimate Universe (Earth-1610). This version had the look, color scheme and size of the Lee/Kirby classics. However, in “Ultimate Comics X-Men” #1 (2011) writer Nick Spencer put the Ultimate spin on Claremont's Nimrod with the Nimrod Model Sentinels. These small but deadly updates of the anti-mutant androids are sanctioned by the government. When mutants are branded terrorists, the president uses Cerebra to locate mutants worldwide and then sends out the Nimrods to round them up.

However, Earth-1610 also has a Reverend William Stryker, and this one is a self-loathing mutant who can control machinery. We'll give you one guess what happens next. Yep, just before the X-Men can stop him, Stryker takes over all the Nimrod Model Sentinels and instructs them to eliminate all mutants. Not only that, he also has them assemble a mega Sentinel to transfer his mind into. We have to say that this Nimrod's history is much more straightforward than the original's, and that is a big plus.

3 JUSTON’S SENTINEL

Juston

In the “Sentinel” miniseries from 2006, written by Sean McKeever with manga-style art by Eric Vedder and Udon, we get a tale that is reminiscent of “The Iron Giant.” Justin Seyfert was a kid that lived with his father and brother at their family junkyard called Seyfert Salvage. He and his younger sibling liked to build robots from scraps from the junkyard and battle them. However, little did Juston know that a microchip he found was part of a Sentinel that had crashed in the junkyard.

When he went to use it in one of his bots, he inadvertently rebooted the Sentinel’s system and it started rebuilding itself. When the youngster discovered the robot, the two made a connection and Juston agreed to help it with repairs and a new directive. After 12 issues of the first volume of their story, this boy and his Sentinel got a 5-issue follow-up series. Their adventures continued in “Avengers Academy" (2011) and then “Avengers Arena.” However, the two were eventually casualties of Arcade's Murderworld in the latter series.

2 CEREBRA

Cerebra

Even casual X-Men fans that have just seen the movies should be familiar with Cerebro. It is the technology invented by Professor X for detecting mutants. You wouldn’t think that basically a helmet could have yet another one of these long and convoluted X histories, but Cerebro does. It went through a number of iterations (including having a body way before the Danger Room did), before finally being put out of its misery. Xavier didn’t just stop needing this invaluable tool though, so he and Beast built a new and improved version called Cerebra.

This seemingly female variant of the detection system, like its predecessor, went through many configurations and rebuilds. In Jeff Lemire’s “Extraordinary X-Men” title, which just started in 2016, the A.I. was put in an old Sentinel shell by Forge and started accompanying the X-Men on missions. It was the first to find Old Man Logan after the incursions that led to "Secret Wars" combined many of Marvel's popular realities.

1 OMEGA SENTINEL

Karima

Our top pick debuted in “X-Men Unlimited” #27 (2000) and was created by Chris Claremont and Brett Booth. Karima’s story is largely about escaping being used as a weapon by others. She was a detective with the Indian National Police force in Calcutta when her chief requested she shadow his son, Neal Shaara. Neal was searching for his missing brother, Sanjit, who had disappeared under mysterious circumstances. The two fall in love while trying to track him down and while they are unsuccessful in their search, they end up getting abducted by Sanjit's captor…Bastion.

The robot menace had kidnapped Sanjit to be part of his Operation: Zero Tolerance program. During the transformation process, Neal’s mutant abilities emerge and he becomes a target for all the other Prime Sentinels in the facility. Sanjit sacrifices himself to protect his brother, but Karima has now become a threat. She's been converted into the formidable Omega Prime Sentinel and begs him to leave before her programming takes over. From there, Karima’s history is all over the place, from being rebooted by Xavier and Magneto, to becoming a digitally possessed Marauder, to reverting back to her Sentinel operating system and attacking her fellow X-Men.

Which version of the Sentinels is your favorite? Sound off in the comments!