BIOGRAPHY
The true origins of the Shadow King are unknown. He claims to have haunted the shadows of this world since the dawn of primal sentience, born as the first nightmare, who will survive so long as one dark thought festers in the hearts of man. Self-aggrandizing poetry aside, little has been genuinely confirmed about this psychic parasite besides the fact that he does indeed exist independent of his most famous host, Amahl Farouk.
In the 16th century, a tale began about a boy named Amahl Farouk. The boy in this tale lived in 
Cairo, Egypt, with his father. The boy’s father was a kind man who raised Amahl ever since his mother died, and also a beloved merchant in the neighborhood. The boy was a burgeoning telepath, who used his mutant gift occasionally to help the people in the market, and his father was quite proud. However, Amahl’s father died of a great sickness when he was only ten years old, leaving Amahl Farouk alone in the world. Alone except for the shadow that spoke from the corners of the room, and the corner of his mind.
The shadow comforted Amahl Farouk and offered to stay with him forever, so he wouldn’t be alone. Without his father, Amahl accepted the nurturing embrace of the shadow. The shadow moved inside Amahl's mind and increased his telepathic powers. In exchange for sharing Amahl’s experiences, the shadow told Amahl tales of its own existence across many worlds. The shadow also encouraging him to use his powers more often, for the benefit of the people in his city. As he grew older, Amahl Farouk used his telepathy to help the people he came across more and more. As the shadow suggested, he used his powers to make sure they were happy. As years passed, Amahl started to lose time and his life in the shadows began to feel more like a dream. Still, he always remembered to use his powers to make his people happy. And they loved him for it. Them for it. For in the shadows, together they were king. [New Mutants (4th series) #14-15]
The tale resumed in 1936, where Amahl Farouk became an unusual ally to the Nazi Party and a contingent of fascist usurpers among British royalty. Lady Regina Windemere had designs on the throne, and Hitler’s Baron Wolfgang von Strucker was willing to aid her in exchange for the new queen keeping Great Britain out of Germany’s war. As a “mentalist and necromancer,” Farouk 
offered a form of spiritual magic which could use the sacrifice of royal blood to end an entire bloodline. Windemere hoped he might “remove” the House of Windsor from her path, while Hitler saw an expedient means of applying his “final solution.” After centuries together, the motivations of Farouk and the Shadow King were one and the same. The King, for his part, enjoyed the role of favor-broker, acquiring debts from powerful parties, as well as the further corruption of humanity as a whole.
Their schemes were interrupted due to a mystical and psychic convergence. One of Farouk’s preliminary sacrifices reached across time and space, calling the Excalibur members Phoenix and Shadowcat back in time from decades in the future. A weakened and confused Rachel Summers was prey the Shadow King could not resist, and he put her under his telepathic spell. Kitty Pryde escaped Windermere’s castle, though, alerting the nearby Alasdhair, Lord Kinross, and his young cousin Lilibet, the future Queen Elizabeth II. Shadowcat managed to prevent the bloodline sacrifice, leading to the death of Lady Windemere and her line instead. Farouk and his Nazi allies’ scheme failed to recover from this, as he also lost control of Phoenix. Through the power of the enchanted Sword of Scone, Shadowcat struck down Farouk’s astral form, leaving him dispersed for a period while they returned to their own time. [X-Men: True Friends #1-3]
[Note: In Excalibur (1st series) #22, Rachel remembered meeting the Shadow King as a teenager, where he mentioned waiting for revenge upon her since before her parents were born. A footnote referred to the upcoming Excalibur Special Edition #3-4 for that story, which eventually became X-Men: True Friends. Farouk also mentioned his appreciation for Rachel’s Hound identity and costume, possibly explaining his use of Hounds similar to Ahab’s creations in Uncanny X-Men (1st series) #265-267.]
The Shadow King was infamous throughout the world at one point. The Penance Council of the V-Battalion knew him as the most accomplished telepath in the world. In exchange for any knowledge he could provide concerning their foes, the Everlasting, the V-Battalion were willing to arrange a détente between their organization and Farouk’s expanding network in Cairo. [Citizen V & the V-Battalion: The Everlasting #2] He had past encounters with Magneto [Uncanny X-Men (1st series) #275] and was even known to Eleanor Murch before she turned into Nanny. [Uncanny X-Men (1st series) #265]
Amahl Farouk established himself as ruler of the thieves’ quarter in Cairo. He had no formal title, yet criminals and authority figures alike knew the price of crossing him, and his empire prospered in the shadows. A humble saloon served as his base of operations, as Farouk’s mind often reached out into Cairo and surveyed his domain. One day, he felt the presence of another telepath in his neighborhood. An American tourist named Charles Xavier lost his wallet to a pickpocket and used his mutant gift to stop the thief. The pickpocket was a latent mutant with vast potential named Ororo, and the Shadow King already had plans for her corruption in the future. To protect his asset and punish the intrusion on his territory, Farouk struck forcefully at Xavier’s mind. The mental bolt was a very painful but very clear message, allowing Ororo to break free and warning Xavier he was in the presence of a master psychic.
Charles Xavier accepted the “invitation” and followed Farouk’s mental emanations to his saloon. Amahl Farouk came down to his private table and addressed Xavier telepathically as they gained 
each other’s measure. Farouk offered an alliance, hoping to sway Xavier and his admitted power to the service of his network of crime. Xavier was a dreamer and a moral man, however, and he was disgusted by Amahl Farouk, down to the very core of his thoughts. Without speaking a word aloud, the two men had become the bitterest of enemies. Xavier challenged Farouk to a psychic duel and Farouk accepted, ready to defend his territory and strike down the upstart who intruded on his affairs.
On the astral plane, the two telepaths worked to intimidate each other and shape their reality for combat. Farouk led with psionic armor and sword, leading the inexperienced Xavier to treat this like traditional melee combat. He then switched tactics and began bombarding his opponent with flames, flames that could change direction and strike Xavier from behind despite his shield. While Farouk prepared his next transformation and continued taunting Xavier, however, Charles became wise to the true nature of their combat. It was not weapons – or even imagination – that won on the astral plane… it was sheer power. Xavier ignored his foe and, as Farouk moved in for the kill, he focused all of his strength into a single psychic shot. This force struck Amahl Farouk like a supernova, devouring his mind and leaving his body devoid of any animating soul. Charles Xavier had won their bout. [X-Men (1st series) #117]
[Note: New Mutants (4th series) #22 claimed the well-intentioned mind of Amahl Farouk interfered with the Shadow King’s success in the events above. It was Farouk who protected young Ororo from being claimed by the Shadow King when it first detected her. It was Farouk who distracted his shadow long enough for Xavier to claim victory.]