Warning: contains mild spoilers for Sabretooth #3!
The the Russian mutant known as Omega Red, a literal child serial killer who was a certified monster before he ever became a mutant super-solider.
When Magneto, Professor X, and Moira X founded the nation of Krakoa, they decided that it would be a land free to all mutants, regardless of their pasts, which at the time sounded like a profound and comionate idea; a way to let any mutant have a "fresh start" in a land where they don't need to fear for their life. However, the way that this policy has played out is ridiculous, and how the Quiet Council has been using the Pit, Krakoa's prison, makes the policy even more hypocritical.
Omega Red is a Russian-born mutant with a long and horrible history as a violent and predatory enemy of the X-Men and all of humanity. During the Krakoan Era, in the pages of X-Force and X-Lives of Wolverine, Omega Red has been used by X-Force and the Quiet Council as a triple agent against Dracula and Mikhail Rasputin, but he has still proved to be a brutal killer with no conscience. Arkady was first introduced in 1991's X-Men #4 as a Russian super-soldier with carbonadium bones and tentacles, as well as mutant "death spores" which kill anyone upon , but it was not until 1996's Maverick and 2018's Weapon X that fans got a full picture of the deadly villain. Growing up in Russia he was feared by his parents and brother because he was constantly torturing and killing animals (as well as humans, unbeknownst to them), before he ed the Russian army. Eventually when stationed at a remote outpost it was discovered that Arkady was a full blown serial killer, kidnapping a series of young girls.
At times, there are mutants whose abilities have made them into monsters, such as Selene and Emplate, who need to feed on humans or mutants to survive. More controversially, Magneto was an out-and-out terrorist, but has since modified his views and was operating in a world where he could be killed simply for existing. Finally, there are those villains like Mister Sinister who have done terrible things but were absolutely vital to making Krakoa safe and prosperous. However, killers like Omega Red and Sabretooth fall into none of these categories, yet they still benefited from the blanket amnesty.
Omega Red has always been a serial killer of his own volition, and there are mutant children all over the island of Krakoa. While mutant can now be resurrected, they can still experience trauma, and villains like the Shadow King have already taken advantage of the island's younger citizens. At the same time the Quiet Council, particularly Professor X, are throwing mutants into the Pit who violate one of the three laws of Krakoa, but otherwise have perfectly clean backgrounds, in a move that is head-scratchingly hypocritical. A curious and mixed-up mutant teen like Melter is confined to the island's bowels by Xavier, while Omega Red is given the chance to run free.
Omega Red has earned no second chance, and yet he gets one by default in Krakoa. While big moves were necessary to secure a united mutant nation, and restorative justice has helped individuals such as Shadow King, the X-Men's casual attitude to a child killer running around their island is difficult to square with the idea that they're operating from a truly heroic mindset.
