Kronos

Kronos is a pivotal major antagonist within the Wondrous Universe canon, having been responsible for many inciting events and being a general menace against the United Republic. A timeless Greek cosmic deity ordaining the concept of time, the ambitious warlord has long lusted for a return to 'Titanomachy', essentially meaning an era where the Titans ruled supreme over all other beings in the Universe, of course with Kronos as their acting head. In a bygone time, Kronos commanded his brothers and all sorts of monstrous creatures from across the veil in a brutal and bloody war against his children to cement his own power. This was because Kronos ate his own children to prevent them from one day usurping him, creating a self-fulfilling prophecy as his wife Rhaea purposefully caused him to vomit up all his consumed progeny and allowed them to escape his spiteful grasp. During this ancient time, Kronos was assisted by other Dark Gods who lent their support, whether through their direct physical presence or the leasing of armies to his cause, such as Morgoth and The Mind Flayer. Despite this however, Kronos would ultimately lose the first Titanomachy, his son Zeus casting him down during a furious final battle over Mount Olympus.
However, this was far from Kronos's end. In fact, one could argue this was the very beginning of his true journey as the United Republicverse began expanding in the modern time. Behind Morgoth, Kronos was the most involved Dark God during this period, having used his disembodied voice that whispered from Tartarus, promising all manner of sociopathic men false promises of great power should they decide to serve him. This had cultivated a colossal cult-following that existed underneath the United Republic's nascent nose. The 'Titan's Loyalists' group proceeded to remain a major thorn in the UR's operations, preventing much of its military from being able to properly transport itself via destroying their supply lines and shipyards with planted bombs. Kronos became enamored with controlling the UR because he viewed that particular Galaxy as one filled with all manner of powerful, unconventional Heroes that wielded a great deal of might and magic. If one could control such a place, he could weaponize individuals like Sergei Vladimir or Rycus Kilran to his own dark ends, creating a new generation of Champions that would act as his Titanic enforcers. 
First though, he needed a new corporeal form, his original body having been destroyed when he was thrust unto the bowels of Hades all those eons ago. It seemed impossible as it stood, despite the best efforts of his loyal minions, often times causing Kronos's mighty yet still non-physical spirit to possess those he deemed 'failures' and forcibly mutate and explode their brain as punishment. Thankfully for the Titan, salvation soon arrived when he was simply allowed to rebuild himself, all the different Kronos particles coming together to reform him at a fraction of his old power, yet still incredibly dangerous. It seemed Hades was emptying the cells of his Realm. The Dark Empire, a mega-alliance of countless villains from across the Multiverse, was forming rapidly with Hades and Sauron as its conceivers, and Hades had saw fit contribute to his nascent creation by staffing much of the armed forces with former prisoners of his, including his own Father. 
Kronos was enraged that his resurrection seemed only to serve the purposes of his inferior son's ambitions, but realized that given Hades's Orb of Corruption and purposeful siphoning of his Titanic power throughout the unknowable eons, Kronos couldn't hold a candle against his rebellious son. So for now, he simply obeyed, though of course plotted in secret. As the Dark Empire's existence progressed, many more thousands upon millions upon even possibly billions of individual Villains joined and were placed in one rank or another, the nation-state ultimately boasting an infinitely large scientific, militaristic, and political arm. This unfortunately also meant that bureaucracy bogged down even the most simplistic of proposals, and given how all the major heads were power-hungry backstabbers that wanted to stab puppies as much as destroy the United Republic, things of importance rarely got done without the Orb of Corruption's mind-control. Kronos noticed this and quickly took advantage, contacting similarly disillusioned parties that despised Hades's control over the Dark Empire and wanted a cooler head in power. 
Beyond simply hating his children for their usurpation and being a natural bastard, Kronos understood that with a warmonger like Hades in charge of such a massive allocation of resources and manpower, he would inevitably turn such potential against potential 'enemies', among which included the United Republic. Despite the Alt-Community of the Dark Empire responsible for much mayhem and sorrow within UR borders, Emperor Pike and the Republican government were still willing to embrace the Dark Empire as allies with open arms months before the War of Darkness broke out. There was a sort detente period after the greater threat of Morgoth had been cowed, but this hadn't lasted long. Hades continued overextending his powerbase and isolating himself in his increasingly unreasonable proposals to wage war on all the DE's immediate neighbors. In spite of their innate superiority, many in the Dark Imperial Senate knew that an over-extension of their already stretched thin assets could spell doom for their gigantic empire. Heedless of their warnings, Hades commissioned the Fallen to invade UR territory, and once that failed, decided to personally involve the DE in a bid to destroy the United Republic once and for all. 
By this time, the other Titans, such as Hyperion, Atlas, Koios, and beyond had been released from Hades's custody or their respective prisons by Dark Imperial efforts, now performing crucial roles as frontline generals for much of the Dark Imperial forces. Kronos decided to recruit his brothers and form the new Titanomachy, now a political faction within the Dark Imperial that was surprisingly moderate in nature, as it wanted to focus on a Peaceful Rise type of expansion effort before engaging in warmongering, whilst Hades's reckless policies demanded immediate action against all perceived foes. The Titanomachy, alongside the Dark Lord Sauron; who had grown equally tired of Hades, and a great many others such as Grand Admiral Thrawn, devised a conspiracy to get rid of Hades. After the fateful Battle of Naboo, in which UR Special Forces had managed to destroy much of 01's 'Human Battery' Farms and thus dealt a great blow to Dark Imperial power-grids (a fate arguably orchestrated by the Titanomachy given many of the clues provided in the coming year), Hades was blamed entirely for the military blunder. Previously, all other losses the DE had experienced were minimal and thus Hades was able to ride the propaganda train to glory, but now with such a loss the hungering politicians out for blood could not be escaped, and Hades, in a twist of fate, was captured and tossed into his own prison-realm by Kronos.
From the instatement of Altmaster Beckett, Kronos and his Titanomachy had been granted a great deal of political and militaristic leeway by the reformed Imperial Government. Using his powers of Time, Kronos foresaw the imminent demise of the Dark Empire at the hands of entropy and over-extension, and so planned ahead, factionalizing much of his assets and ensuring those under his banner were kept loyal only to him and his ultimate goal of slaughtering his traitor-children and becoming the Supreme Multiversal Entity once more. The DE made attempts to leave the war, given as now throughout the Multiverse rebellions were snowballing due to mass dissatisfaction with Imperial occupation and egregious mismanagement of resources during the Hades era. Beckett fixed what he could and managed to save the Empire from total damnation however, much thanks to Kronos's assistance.
Kronos then devised a ruthless plan with Beckett and other Imperial autocrats that sought to ensure the Dark Empire's survival from the unceasing tidal wave of civil war, internal political schisms, external empires smelling the blood in the water, and much more now tearing at the seams. This was Operation Changing Histories. Changing Histories entailed the sudden disappearance of much of the Dark Empire's colossal resources depots. In fact, even entire planets, all of which were lucrative and provided a great deal of mineral or economical wealth were gone without a trace. As the Dark Empire had by now entirely ignored Altmast Beckett's authority given the lack of an Orb of Corruption, using a network of altered terraforming equipment and Kronos's Titan powers to perform all this had been immensely easy, as everyone was too busy killing each other to notice this. 
These disappeared assets would reappear in unexplored echoes of space. The Unknown Regions provided a delicious cover for Operation Changing Histories, in which Kronos and Beckett would establish a genuinely official 'Dark Imperial Remnant'. By the time Sauron's final effort to destroy the United Republic ended in failure and his spirit's banishment into Handos, the true continuation of the Dark Empire was prospering whilst the so-called 'official' heirs led by politicized figures like Woke and Kledji were engaged in wars of attrition against each other to merge together. The Dark Imperial Remnant governed itself from Arcturus, a once effervescent natural world that Kronos had sped up to a desolate era, as to make room for all the Dark Imperial equipment that now established itself onto the planet. 
Using his Titanic magic in coordination with his Brothers, Kronos had also managed to stuff the world full of resources and even grant it a degree of sentience so it may act as their Mobile Commander Base. The Titanomachy grew akin to a beautiful parasite from within the Imperial Remnant, now gathering new and old evil creatures under its banner like the wretched Harpies and monstrous Cyclops of yore. Kronos wasn't adverse to recruiting non-Greek minions however, as such many Norse Ice-Giants also flocked under his lordship upon hearing that a great ruler existed within the Unknown Regions. 
Beckett managed the internal day-to-day political scheming of the Dark Imperial Remnant whilst Kronos handled the big picture, often leading daring offensives to capture new territory and subsume the local populace as servitor-races of their cause. However, Beckett grew increasingly suspicious that the Titanomachy, who were a majority of the time the vanguard for any Dark Imperial push into a new Solar System, were pocketing much of their gains for themselves. Of course, he was powerless to act on it. 
Kronos fostered the Neo-Titanomachy to grow into an entity of its own, marketing it as the 'vanguard vassal' of the wider Dark Imperial Remnant, but in reality working his power of manipulation and statecraft to ensure that a string of Solar Systems did not owe allegiance to Beckett or the Remnant Council, but rather Kronos exclusively. Kronos also worked to curb the power of the Remnant Council, consisting mostly of old-age Dark Imperial officers, EITC trademasters, Nemoidians, minor Lovecraftian deitites, and some others on many occasions, succeeding always given their lack of willpower and they themselves being fractured on a multitude of issues so deeply they could never realize that Kronos was always their enemy. 
The Neo-Titanomachy proved difficult to manage though, as immigration into these systems often meant eternally high amounts of crime and civil unrest, alongside daily natural disasters on some of the more unstable worlds citizens were corralled into. Kronos cared little for the suffering of his people though, only keeping them around for their usefulness to his goal of revenge. It is from here Kronos begins more personal manipulations, now working to disrupt the life of one Percy Jackson, a son of Poseidon who has proven quite a destroyer of Kronos's more secretive plans to rule the Universe and twist the gods against each other to keep them occupied and weak whilst he prepared his power in the Neo-Titanomachy. Above all, Kronos is always a schemer that thinks one step ahead. For now, he remains cooperative with the Dark Imperial Remnant, but it is folly to believe he shall remain hidden away forever. Whatever Kronos is planning, it will affect the entire Multiverse with its magnitude, and surely bring about the end of the Greek Pantheon.