Alternate Reality Versions
This plan was contraried both by Magneto's anger to see his daughter used in this way, destroying all the clones except for one, and by the attack of Omega's troops. Jean Grey was forced to operate quick, and her actions led to the depoweration of only her and her fellow X-Man Sabretooth.
The virus was developed by two scientist from the South East Asian Republic (SEAR), with low-intensity symptoms, inoculated to several people send to travel, in order to spread it. It function was to prevent the contraction of the X-Gene, which itself originates from a virus, and in essence wipeout the the human mutant genome.
It was the first step of The Plan for the SEAR to win the super-human weapons race, the second being The Source as the first step of.
"No more powers" (Earth-9021)
At the end of the House of M, the Scarlett Witch pronounced the words "No more powers", depowering all powered beings on Earth, including Mutants, Inhumans, mutates or Skrulls. The only power left was the Cosmic Cube.
A massive human depoweration and hecatomb happened there, as the U.S. soldiers were equipped with Mutant cure-loaded guns and canons, and as the Dark Phoenix rose, killing numerous members of the Brotherhood, including most of the Omega Gang. Magneto himself was depowered, but it was believed that his abilities were slowly coming back.
The Decimation was caused by the Human Coalition's actions after Albany, New York,'s destruction by the Phoenix. The mass production of Exonims and the intensive track of mutants and possible X-Gene carriers grandly diminished the mutant population.