WARNING: The following article contains spoilers for Uncanny X-Men #22, by Matthew Rosenberg, Salvador Larroca, David Messina, Guru-eFX and Joe Caramagna, on sale now.

One of the deadliest eras in X-Men history has come to a close, and several major heroes died in its final moments. While most of the X-Men have spent the past few months in the "Age of X-Man" reality, Cyclops and Wolverine have led a ragtag group of mutants in a world that hates and fears them more than ever before, due to the mutant-hating General Callahan.

As the X-Men have hunted down several of their old villains, they've watched friends and foes die, suffer devastating injuries or be de-powered in unprecedented numbers. In a desperate last attempt to save what remains of mutantkind, Emma Frost amplified her telepathic powers to make Callahan's forces, and the rest of humanity, forget the existence of mutants.

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While Frost's efforts initially seemed successful, Uncanny X-Men #22 revealed Callahan still remembered who the X-Men were, and had control over his powerful new Sentinels, built with alien Technarch machinery.

As Cyclops and his brother Havok talked in a park, Callahan sent his Sentinels after them. To help his brother get away, Havok seemingly sacrificed his life to unleash a massive burst of cosmic energy that vaporized both Sentinels.

1093 Havok Death

While Havok's powers have always been somewhat unstable, they've been unusually unpredictable since he was experimented on by Callahan. Alex Summers nearly tore himself apart with his own mutant ability after defeating Mister Sinister a few issues earlier, and the longtime X-Men leader was seemingly disintegrated by his own powers here.

As the Sentinels advanced on the Hellfire Club Mansion that contained the X-Men, they vaporized one of the team's newer allies, Fabian Cortez. Although this one-time Acolyte of Magneto was fairly prominent in the early 1990s, he hadn't had a meaningful appearance in the past decade. With his ability to amplify other mutants' powers, Cortez was essential to helping Frost to enact her master plan.

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Through the Office of National Emergency, Callahan used technology harvested from the techno-organic alien Warlock, a former X-Man and New Mutant, to construct the new Sentinels. After taking a direct energy blast from one of the Sentinels, Warlox, the bonded form of Warlock and a Jamie Madrox duplicate, tried in his final moments to reformat the Sentinels programming.

Although Warlox's efforts were briefly successful, Callahan quickly reactivated the Sentinels and continued his assault on the X-Men. In a final, desperate act, Jamie Madrox, the Multiple Man, used his powers to create duplicates to serve as a human shield, to help Wolverine reach Callahan. For the often-reluctant hero, this was the ultimate act of bravery, and it cost him his life.

1093 Wolverine Madrox

Once Logan reached Callahan, he promptly sliced the general in half. While that didn't stop the rest of the Sentinels, the rest of the X-Men returned from the Age of X-Man, just in time to save their teammates and overwhelm the robots. As the team began to tally its losses, the X-Men destroyed Frost's Cerebro unit, undoing her planet-wide memory wipe, and stood united in front of the world once again.

Since this X-Men era kicked off with the resurrection of Cyclops a few months ago, almost 30 named X-Men characters were killed, and a few others suffered massive injuries or were left in more uncertain states. While a fraction of these fatalities would define any other period in X-Men history, this showed what would happen if mutants were as hated and feared as they're often billed.

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While the total annihilation of Genosha and the original "Mutant Massacre" crossover killed off more characters in total, the X-Men have never lost this many familiar, fan-favorite players in such a concentrated time span.

With House of X set to kick off a major new era for the X-Men next week, Cyclops and Wolverine's ragtag X-Men team could've easily been a footnote in X-history. However, this era of Uncanny X-Men and its related titles represent one of the darkest, carnage-filled moments in the history of Marvel's mutants. Hopefully, the dawn of a new age brought on by House of X will lead the X-Men to a brighter tomorrow.

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