The Decimation was one of the most dangerous periods in Marvel history to be a mutant. The events of House of M reduced the population of the super-powered minority around the world. No felt the brunt of this event more than the X-Men, who tried to keep the last mutants alive in an increasingly dangerous world.
Now, CBR is looking back at the history of the Decimation and the effect it had on the Marvel Universe.
WHO SAID NO MORE MUTANTS?
The Decimation occurred as a direct result of House of M. Following Scarlet Wtich's mental breakdown in Avengers Disassembled, the X-Men and Avengers debated how to treat Scarlet Witch. While they argued, Quicksilver compelled her to her powers to create a new reality, providing every character with their ideal life. This included Magneto, who was remade into the monarch of a world where mutants have become the dominant species in a moderately happy world. However, the heroes slowly had their memories restored, leading them to revolt against Magneto's regime.
The rebellion led to the discovery of these machinations. Enraged that his son would use his name to remake the world, Magneto beat Quicksilver to death. Scarlet Witch furiously restored Pietro to life and berated Magneto for always caring about mutants over his family. Taking her vengeance on the thing Magneto loved more than them, she declared "No More Mutants". When reality was reset, roughly 98% of Mutants all over the world lost their powers.
WHICH MUTANTS KEPT THEIR POWERS?
The world quickly took notice of the Decimation. Although the number was never confirmed, only 198 mutants in the world were thought to have kept their powers. The X-Men quickly assembled many of the remaining mutants at the Xavier Institute, trying to watch over the remaining population of Mutants. However, the Church of Humanity managed to reduce the number of mutants even further. The Mansion was eventually destroyed during the Messiah Complex crossover, and the the X-Men to relocate.
After that, the "Manifest Destiny" era saw the X-Men briefly move to San Francisco, California. The group created Utopia, a mutant city-state, as a new base of operations and sanctuary for mutant kind. Cyclops led the X-Men during this period, becoming more militaristic in the process. Cyclops even eventually assembled X-Force as a proactive force to protect the few remaining mutants by targeting threats before they could attack.
HOW DID MUTANTS GET THEIR POWERS BACK?
The events of Decimation played a major role in setting up the Schism that broke apart the X-Men. Cyclops took the events of the Decimation to heart, deciding that the next (likely last) generation of mutants be soldiers. With Beast's support, Wolverine came to the conclusion that they should be teaching them as students. This debate eventually turned violent, and the X-Men fell into civil war. At the end of the conflict, the team split into two versions of the X-Men, with Cyclops leading the Utopia-based group while the rest returned to New York.
These tensions were exasperated during the events of Avengers vs. X-Men, where Cyclops and four of his lieutenants (Emma Frost, Magic, Colossus, and Namor) were granted the Phoenix Force meant for Hope Summers, a mutant messiah. The conflict eventually forced the entire superhero community against Cyclops, who was consumed by the power of the Phoenix Force. He became the Dark Phoenix and killed Charles Xavier under the Phoenix's sway. Eventually, Hope and Scarlet Witch worked together to bring the energies of the Phoenix out of him.
This resulted in a massive outpouring of energy that managed to spark the mutant population once again. It didn't reverse the events of Decimation, but it created entire new generations of mutants. While it only took six years for the Decimation to be reversed, but the period quickly became one of the most distinctive and dramatic periods in recent X-Men history.