Chaos (The Power of Five)

The King of the Old Ones, known by mankind as Chaos, is the primary antagonist in Anthony Horowitz's novel series The Power of Five, spiritual successor of his unfinished (and more light-hearted) series Pentagram. He and his servants, the Old Ones are based on the eponymous Eldritch Abominations from the works of Howard Philips Lovecraft.

Nature
Chaos is the incarnation of Evil and the direct or indirect source of every woe that befalls the world. He was created along the Earth and has existed for billions of years. It is possible that all the mass extinctions that happened in the earliest stages of history empowered him, given that he feeds off pain, displeasure and suffering.

Chaos is described as a mountain-high, unfathomable abomination of humanoid frame, whose aspect is far too huge and too horrifying to be fully grasped. (Much in the same was as Cthulhu, of whom he is likely inspired.) His body is covered with spikes, his skin is scaly, his eyes are glowing red, and he wears a crown. Alternatively, he often appears under the aspect of a human-like figure made of pure darkness, akin to a living black hole.

Chaos is a deceitful shape-shifter and a skilled manipulator, as well as a frighteningly powerful being, able to manipulate the environment, the elements, and humanity to his will.

He is unspeakably cruel, merciless and sadistic; killing and torturing his foes as horribly as possible, caring only for his followers when they are of use to him and never forgiving any mistake. He does grant his most competent followers the wealth and influence that they crave, as long as he needs them, and promises a quick and painless demise to his foes should they surrender. Yet he hardly veils his disgust for mankind, which he plans to obliterate as soon as his foes are defeated for good.

Being pure evil, he knows only about the ugliest aspects of mankind, and is absolutely unable to fully grasp the way humans behave. He is so arrogant that he fails to consider that even hardened criminals could cast greed aside to rise against him, or that the Five could defeat him a second time, and his utter unability to learn from his mistake would ultimately spell his doom.

Origins
Chaod eventually came to Earth after the rise of mankind. He appeared like a black nightmare, like the nightmares of the world bought into daylight. He first manifested in the country that would become China along with his generals: infernal demons called the Old Ones, and set out to cleanse Earth of mankind, which he considered horrible.

Chaos killed millions and enslaved mankind. He gained the obedience of the greediest upper class, granting their wishes of wealth and falsely promising that they could rule with him. But he later showed his true intent when he put his rich followers in the front lines during battles during a battle. Chaos and the Old Ones ruled Earth for centuries, wrecking human settlements all over the world.

However, in the middle of the war, Five children called Matt, Inti, Sapling, Flint, and Scarlett (but everyone called her Scar), were born in what would become England, Peru, America and China respectively. (In these ancient times, said countries were very different from now, even more so due to the Old Ones' influence.) Five children with immense powers, who when together would be able to defeat the Old Ones. Chaos drew black and purple clouds round the Earth to bloat sunlight and darken the world; and put rubbish in the oceans so life wouldn't grow. As such, the Earth was slowly dying.

Chaos thought he had finally won when Matt played a trick on the Old Ones, by sending Sapling to his death, but little did he know that the Five could be reborn in the future. This sent the future Sapling (called Jamie) back in time to complete his mission. Jamie succeeded in meeting the other Five, who all stabbed Chaos' heart. Chaos was dispersed into black ash after screaming all over the universe, as if "he had turned into night  that was slowly fading away". A gate then opened up and sucked Chaos and the Old Ones into Hell.

Matt and the other Five created two Gates, one in the future England and the other in the future Peru, to keep the Old Ones from resurfacing. Indeed, they were not truly dead, only banished, and would one day return.

Raven's Gate
The Old Ones nearly returned ten thousand years after their banishment, when a cult of witches and wizards from Yorkshire in England planned to set them free.

They captured Matt's reincarnation and took him to their coven to sacrifice him during a nuclear meltdown, but Matt's awakened power enabled him to flee. Since only a drop of Matt's blood was shed when the ritual required all of it, Chaos could only partially resurface, long enough to kill his now useless follower Sir Michael Marsh, and was sucked back into the Abyss.

Evil Star
All the other Gatekeepers (the modern name of the Five) had been reborn as well, so Matt met Inti, who was now called Pedro, in Peru; while trying to prevent the opening of the second gate.

Diego Salamanda, an influential businessman and worshipper of the Old Ones, managed to open the gate, in fact the Desert of Nazca, and Chaos and the Old Ones came out of the Earth. Knowing that they needed to be Five to defeat him, Chaos laughed off Matt's challenge and crippled him to near death. Fortunatelly, Matt combined his powers with Pedro's and severely wounded the King of the Old Ones, forcing the demons to disappear into the night.

Nightrise
Chaos gathered all his followers, and corrupted many of the most greedy world leaders and businessmen, whom they assembled into an immensely influential secret society called Nightrise Corporation, tasked to open the way for the Old One's rise into power.

Nightrise set out to abduct children gifted with supernatural powers and discovered two Gatekeepers, the Native-Americans twins Jamie and Scott. They abducted Scott, breaking his spirit through horrible tortures, and made him into a vegetative puppet. Wanting to have one of their operatives as President of the United States, they used Scott's telepathic power in order to kill Senator John Trelawney (an expy of Barack Obama) to dispose of obstacles. Although Jamie managed to travel back to the past to banish the Old Ones, to save his brother and to thwart the plan; the unfortunate Scott could never fully recover, and Nightrise rigged the elections and gained control of the U.S. for the Old Ones.

Necropolis
The Old Ones and Nightrise based themselves in Hong Kong and turned it into a city of the dead under Chaos' complete control. The King of the Old Ones intended to start a war from it, and had Nightrise lure Scarlett, the last Gatekeeper, in town to get rid of her. With help from Matt and Jamie, Scarlett escaped from Nightrise's grasp and conjured a typhoon which destroyed Hong Kong, but was shot and severely wounded by a Nightrise agent. Alas, Chaos did not care about it and returned to his true headquarters, a grand ice palace in the Antarctic called Oblivion.

Chaos waited for the Five to use one of the gates that could transport them everywhere in the world, and trapped it to scatter them all around the world, ten years into the future.

Oblivion
With his enemies out of the way, Chaos destroyed the gates to hinder them when they would return and revealed himself to the world, setting out to take it over. Chaos did much the same thing as before: He set about manipulating and brainwashing as many people as he could, falsely promising wealth to his followers, expanded his influence all over the world and killed billions. When the Gatekeepers and their allies resurfaced, the Earth was reduced to gloomy hellhole with mankind close to extinction, where even those who opposed the Old Ones were prone to ruthless violence.

The Gatekeepers reappeared in different parts of the world and managed to escape the Old One's followers, but Nightrise took profit of Scott's mental scars to gain his obedience and used him to capture Pedro, who barely managed to flee. Some of the Gatekeepers managed to reach Antartica with help from a global coalition, but the coalition's army was crushed by Chaos' forces. Chaos used Scott as a bait to lure Matt to his palace, where he captured him and tortured him. However, Matt had learnt about his fate and let himself get caught. Matt's guardian Richard Cole who was captured with him had no choice but to kill Matt, to bring his past self into the present time. Later, Scott wracked with guilt sacrificed his life to restore the gates and enable the remaining Five to reach Oblivion. Chaos confronted the remaining Five, but Matt's and Scott's past selves barged in and the reunited Gatekeepers stabbed Chaos through the heart, destroying him once and for all and banishing the Old Ones into Hell. Before the gate could close, the coalition sent as many nuclear bombs as they could into the Old Ones' dimention, obliterating them.

Then the Five's past and present selves were reunited and they all departed forever into the Land of Dreams. The coalition formed a peaceful global government overseen by the Five's allies, and the Earth started healing.

Quotes
"The power of the Five has been defeated... One of you has been trapped far from here and another of you has been killed. He died painfully. Now lay down your arms and I will give you a quick death. The rest of you I will allow to serve me. There is no need for this battle. You know it has already been won."

- Chaos challenging Matt before his first defeat

"Two of the Five! But not enough! Three of the Five... but not enough, still not enough!... Four of you!"

- Chaos' last words before his first defeat and imprisonment