Sauron - Rank 6 in the House of X's leadership, a Mutant with the ability to transform into a colossal, pterodactyl-like monster with the ability to drain life energy. Named Karl Lykos, he was born in Greece and had a somewhat normal life for a mutant, manifesting his mutation safely at home and without either of his parents hating him for it. However, Lykos always had a bit of a disturbing side, often spending time burning away ants and resenting almost everyone he met. These odd habits grew into misanthropy as he grew up, but his high intellect and overall agreeability in personal affairs led him to bottle up these feelings most of the time, instead seeming perfectly normal and even extremely kind and nice to other people, quickly being seen as a philanthropist once his studies of biology got him enough money to give to charities - however, he only did this to feed his own ego, seeking praise by performing good deeds. He became a famous biologist, but quickly became bitter once he lost a Nobel peace prize to Moira McTaggert's legendary thesis, Understanding the Abhorred, a large book about the X-Gene, its manifestations, and how to understand the powers of mutants and how to teach young mutants how to come to terms with their powers - the book was angled towards humans, and tried to convince people to empathize with mutants instead of seeing them as an other, and the scientific breakdown of the X-Gene and mutations within shocked the world, snatching the peace prize from Lykos, who was nominated for a monumental experimental study on the creation of artificial meat to bypass not only moral concerns of farming animals but also ecological ones. Lykos felt her book wasn't even comparable to his breakthrough, and resentment bubbled and boiled in him.

He eventually came to hate almost everything Moira touched, his mad obsession with her poisoning his view of the x-men, Charles Xavier, and even civil rights for Mutants in general, despite he himself being a mutant. Sensing this hate combined with his understanding of biology, Cassandra Nova eventually recruited him into the House of X, to serve as their expert in non-mutant biology (as opposed to Essex, who is a mutant scientist first and foremost), in return for a chance to ruin the dream of both Charles and Moira. He accepted and quickly began work in secret, still putting up his amicable public face. He seems very nice and calm most of the time, even if there is an undeniable creepy undertone to his behavior and way of speaking, and to most just appears to be a kind philanthropist and scientist, but underneath this veil he is a horrible, cruel man who is filled with hate and envy to almost everyone, even his fellow HOX members (except Cassandra, who he rationally fears instead), and loves seeing them suffer and fall apart before him, considering it justice for how much he's suffered at the hands of the world in his eyes. He's prone to long winded, mocking rants about how his enemies are breaking down, or what ways they're inferior, and similar such things, often laughing a distinct, refined yet annoying cackle all the while. He normally wears white dress clothes, but never a suit or coat. In his mutated form, he appears as a massive dark green pterodactyl-like creature, with six glowing red eyes, giant claws, four wings, and a tail that ends in a blade. His eyes normally are blue, but turn opaque red whenever draining people of energy, even in human form.