On M-Day , the mutant population was reduced from the millions to just a couple of hundred. Having gone from being considered the next step in human evolution, mutants are now an endangered species. The X-Men 's resident scientist, Hank McCoy - better-known as Beast - decides to do something about the Scarlet Witch 's mass-depowering of mutants (during HOUSE OF M ) in an attempt to solve the unsolvable... [AGE OF APOCALYPSE - first appearance of the Dark Beast] [HOUSE OF M - the Scarlet Witch depowers the mutant population] [DECIMATION - the immediate fallout from House of M] X-Men: Endangered Species #1 X-Men #200 [2/2] Uncanny X-Men #488 [2/2] X-Factor #21 [2/2] New X-Men #40 [2/2] X-Men #201 [2/2] Uncanny X-Men #489 [2/2] X-Factor #22 [2/2] New X-Men #41 [2/2] X-Men #202 [2/2] Uncanny X-Men #490 [2/2] X-Factor #23 [2/2] New X-Men #42 [2/2] X-Men #203 [2/2] Uncanny X-Men #491 [2/2] X-Factor #24 [2/2] X-Men #204 [2/2] X-Men: Endangered Species #1 Having learned of the death