Fabian Cortez

Fabian Cortez is a fictional mutant supervillain appearing in American comic books published by Marvel Comics. The character is depicted as an adversary of the X-Men. Created by writer Chris Claremont and writer/illustrator Jim Lee, he first appeared in "" #1 (October 1991).
Fictional character biography.
Acolytes.
Thought to be royalty from Spain, Fabian Cortez organizes the original Acolytes, who pledge themselves to Magneto and his cause. Cortez then goads and manipulates Magneto into combat with humanity and the X-Men at every turn, leading to the destruction of Magneto's space-station, Asteroid M, and the deaths of the other Acolytes, including Cortez's own sister Anne Marie.
Cortez recruits a group of Acolytes who, believing Magneto to be dead and martyred for his cause, now worship him as their god, to follow Cortez in Magneto's name. They launch several strikes on humanity, ranging from attacks on a military base where new Sentinels are being built, to slaughtering helpless humans in a hospital. Magneto eventually resurfaces, sending his chosen heir Exodus to inform the Acolytes of Cortez's betrayal. The Acolytes welcome Exodus as their new leader, and Cortez is left behind.
"Bloodties".
Fearing Magneto's wrath, Cortez flees to Genosha. Still claiming to speak in Magneto's name, he incites the nation's mutant population into starting a civil war against the humans, the world's first instance of the long-threatened genetic war between man and mutant. With the aid of the mutates, Cortez kidnaps Magneto's granddaughter Luna, intending to use her as a shield to protect himself from Magneto, the X-Men, and the Avengers. Cortez is unaware that Magneto had recently been mindwiped by Charles Xavier, and Exodus comes to Genosha in his place, seemingly killing Cortez.
Back with the Acolytes.
Cortez reappears months later, claiming to have been badly injured, yet not actually killed, despite all appearances. He manipulates Joseph into posing as Magneto, pitting him against Exodus in an attempt to regain control of the Acolytes. Despite his scheme's failure, he is allowed to return to the team. Months later, at a time when Exodus had briefly been imprisoned, the Acolytes split into two groups, each searching for Magneto. Cortez leads one group, but they abandon him during a battle with the X-Men, upon realising how he has been using them for his own purposes.
Dark Seduction.
Alone again, Cortez is surprised to be recruited by Magneto himself, whom the United Nations has given control of Genosha. Seeing as how Fabian Cortez had betrayed him earlier, Magneto only lets Fabian Cortez serve him on Genosha because his powers have been reduced and Cortez's mutant power is to heighten the abilities of other mutants. After a further betrayal by Cortez, discovered by Magneto's UN advisor Alda Huxley to be the leader of the Genoshen cabinet assisting a rebellion in Carrion Cove, Magneto is restored to full power by one of the Genengineer's machines and as he no longer needs Cortez, pulls him from a prison in Hammer Bay, to over fifty miles away to Carrion Cove in less than 20 seconds. The impact kills Cortez instantly, as he splattered on the ground at Magneto's feet. Just before his death, a connection between Cortez and the geneticist Mister Sinister was implied which would explain how Cortez returned alive and well when everyone believed him dead by the hands of Exodus.
Necrosha.
After the X-Men form Utopia, Magneto joins them, saying he supports their efforts. Selene especially wants Magneto captured for his collaboration with Emma Frost to overthrow her from her position as Black Queen of the Hellfire Club. She has three of her recently resurrected mind-controlled soldiers—Acolytes Cortez, Delgado, and Mellencamp—hunt down Magneto. They try to torture Loa to get the information out of her, but when she tries to hide in her room she finds Deadpool inside it. Deadpool battles the trio, but the techno-organic virus that is inside the Acolytes (which caused their resurrection) prevent him from killing them. At one point in the battle, Cortez grabs Loa by the throat and demands to know Magneto's location, saying that even though Selene wants Magneto alive he will fight the mind-control and kill him anyway. Loa begs Cortez not to make her hurt him, something Cortez does not believe possible. Deadpool knocks Loa out of Cortez's hands, but then is overpowered by the Acolytes. Loa uses her matter disruption powers to slide through Mellencamp, mutilating him. Deadpool, seeing that Loa's powers were able to slay Selene's minions, forces her to kill Cortez and Delgado too by throwing her into them (to survive, she has to slide through them, which causes them to crumble). Deadpool then tells Cyclops that he should not be in trouble because Loa had done all the killing.
The techno-organic virus however appears to reform Fabian Cortez, as he resurfaced later along fellow Upstarts members Shinobi Shaw, Siena Blaze and Trevor Fitzroy, and started the game that they created long ago. They killed members of the Nasty Boys in order to lure out Cyclops and his ragtag team of X-Men to Washington Heights. After a brief moment of words, the two groups engaged each other in battle. The X-Men gained the upperhand as the Upstarts retreated but Shinobi was left behind, only to kill himself as he didn't wanted to get captured or be controlled by the Hellfire Club.
Powers and abilities.
Fabian Cortez possesses a unique mutation which grants him the ability to enhance or diminish energy levels. In the cases of mutants, he can enhance their abilities to occasionally to very dangerous levels and limits of which may exceed the normal limits of the targets' control; temporarily empowering them at the expense of the targets' health. Thus, burning out the targeted subjects physical bodies, sometimes on the molecular level. 
In X-Men #1 (1991), while on board Asteroid M, Magneto returned from a fight with the X-Men having suffered deep lacerations to his lower abdomen from Wolverine's claws. Cortez seemingly "healed" Magneto, as he said he had also done with his sister after an earlier battle. These actions temporarily restored Magneto back to full health and vitality. However, these actions turned out to be a false as the effects on Magneto were needed frequently to sustain the "healing" effects by Cortez. Whether this was an offshoot of Fabian Cortez's main powers, a display of "controlled power boosting", or demonstrations of an ability to "trigger" a mutant's own natural healing abilities is not known. This ability was not used much or at all in his later history. Additionally, it has not been clarified if his power affects human bio-energy or other natural occurring energy in the same manner.
Cortez could also use his powers to interpret and sense the genetic code of living beings and unique bioenergy signatures and energy fields in other mutants. Likewise, he may also have had some control over his own energy field along with possibly being able to constrict it around a target, various targets and foes.
Cortez is also a skilled martial artist and often carries a firearm. It has not been yet clarified if his skill sets are rooted in a previous military background, resulting in advanced tactical expertise. Still, he is noteworthy to mention that he is highly intelligent, tactical, and a formidable military strategist.
Other versions.
"Marvel Zombies".
In the "Marvel Zombies" reality, Magneto heads to earth to rescue anyone he can from the zombie plague. Fabian is entrusted with overseeing Asteroid M and preparing it for the last outpost of humanoid life. Cortez does this well; his group soon joins up with other survivors, including Forge and the Black Panther. Magneto perishes in battle against the zombies. Decades later, in "Marvel Zombies 2", Fabian's child regains control of the colony during a battle with cosmically powered zombies.
"X-Men Forever".
In this reality shortly after the X-Men escape the destruction of Asteroid M, Nick Fury enlists the X-Men in helping him find and capture Fabian Cortez. The X-Men successfully capture Cortez, though he nearly defeats them single-handedly.Fabian Cortez was eventually turned over to S.H.I.E.L.D., but corrupt agents within then gave him over to the anti-mutant Consortium. Eager to exploit the "burnout" (that reality's phenomenon where mutant powers cause people to physically give out and die early), the Consortium thought Cortez's powers were rife with potential to weaponize the concept. Weeks later, Cortez was rescued by Nick Fury and the X-Men, but was on the verge of death due to the experimentation he was forced to endure. Cortez died in X-Men custody shortly thereafter.
X-Men '92.
Fabian Cortex appears in X-Men '92 when he overcharges Lila Cheney's teleporting powers and she takes the X-Men to a distant planet inhabited by mutant Brood.
What If.
Fabian Cortez appears in a number of "What If...?" issues.
In the reality seen where Tony Stark chose not to begin a super-hero career as Iron Man after returning from captivity. Fabian Cortez and the Acolytes assembled under Magneto and battle both the X-Men and the StarkTech Sentinels that threatened mutant lives after Tony Stark's innovations to America's Sentinel program had shoved the mutant race to the brink of extinction.
In the reality seen where the space station Avalon was officially recognized as a mutant colony under the rule of Magneto, divisions grew between his Acolytes, with Exodus leading the isolationists who wanted to take Avalon to the stars and away from the taint of humanity on Earth, while Fabian Cortez's annihilationists wished to return to Earth, eliminate the humans, and reclaim their homeland. These concerns became secondary after the birth of Acolytes Skids and Rusty's first child, who registered as Homo Ultima, the next stage of humanity beyond even mutants. Cortez and Exodus united their factions in fear of being usurpted, leading to the death of the child. In the aftermath, it was revealed that Magneto engineered fake genetic scan results for Homo Ultima, sacrificing the child in order to bring unity among his Acolytes again.