Grand War
Starting with a war on the continent of Lancil, the Dark God Tarrent managed to convince his following to sail across the dangerous oceans and invade Plutis once more. Once the navies were prepared, they set sail, and a year later, arrived upon the Northern shores of Plutis. Unlike the last two invasions, Tarrent was around to grant his followers immense power- Power, that they used to set up a portal back to Lancil. With a portal in place, the massive armies stormed through, providing a more formidable enemy than the prior invasions. Countless legions of Orcs, Goblins, Kobolds, Demons, Devils, and other monstrosities marched out of the dark, purple portals.
The army laid waste to the Dwarven settlements and ports along the Northern Rim of the continent, slowly spreading South. They started pushing into the Dwarven heartland, before being repulsed by a formidable Dwarven counter-attack. After a several month long stalemate, the Dark Army managed to make a breakthrough- Not into Dwarven lands, but through the mountain passes and tunnels into Draconia. The fighting in Stendanair subsided, as Tarrent's army pushed into the Dragonborn homelands. For thirty years, they held the army back, before their capital fell. And after it fell, darkness spread across the land. Blights, plagues, famine, drought, floods- Terrible horrors spread across the lands, preceding the Dark Army. As the shattered Dragonborn army withdrew to the South, countless refugees flooded the still-open tunnels and paths to Stendanair, Tempest, and Merentha.
One by one, the tunnels through and paths over the mountain ranges were sealed by the humans and dwarves, until there was only one path left: the causeway into Tempest, the human/elven nation. Despite their best efforts, the Tempest Army and Dragonborn Remnants were unable to stop the overwhelming force crashing down upon them. A en evil, foreboding creature was leading the army now, and when the horde arrived at Steadfast, the magnificent silver capital of Tempest, the creature raised its hand and destruction reigned.
Meteors crashed from the sky, the blood of its citizens boiled inside their bodies, and fires spread like disease. As the city burned itself to the ground, the creature then showcased one final act of power- slamming its arm down into the ground, a massive explosion of crystal and rock erupted around him. Black spikes jutted from the ground throughout the city, destroying it utterly. As Steadfast fell, the lands of Tempest began to dry out, turning the thriving jungle lands into a barren desert wasteland.
News of the destruction of their neighbor rocked the Elven Grand Priest, forcing the Elven armies to enter the fray. With three great nations and four fronts being fought on, the Dark Army withdrew temporarily, seemingly to grant their leader a respite. While they waged war, the Dwarven Queen, Elven Grand Priest, and Human Emperor hatched a bold plan- Utilize potent magical items to drain the portals that were being used to summon reinforcements, and then turn that collected power on the Dark Army itself. Six Great Warriors from across the lands managed to steal and seal the portal magic into five mystical artifacts: A bow, a sword, a shield, a staff, and an amulet.
Having de-powered all but one of the portals feeding the Dark Army, the now-united Grand Alliance pushed the Dark Army back, crushing them with victory after victory, before laying siege to their last stronghold, and home of a massive portal under construction: Jahanna. It was in this battle that the leader of the Dark Army finally revealed himself- The Dark God Tarrent himself, wielding the Dragonborn leader, the NeoCount, as his avatar. He slaughtered one of the Great Warriors, before ripping out her soul's essence. Tarrent mocked the Great Warriors, ex-positing his plan to use the souls of the defeated to power his portal, granting him a way to bring in his most powerful and world-destroying creatures from other planes. Using the power of the mystical artifacts, one of the Great Warriors sacrificed himself to serve as a conduit to focus them against Tarrent.
With a massive explosion, the Dark Army was engulfed in a dark purple swirling dome of energy. Stuck into the side of it, was the Amulet of McGuffin, focusing and holding the dome together. The Great Warriors realized that Tarrent was trapped, and that their other artifacts were powering it. They lied to the generals of the Grand Alliance, claiming that they had defeated the Dark God, and the resulting dome was merely an aftereffect of using so much power at once. Reluctantly, they believed them, but not before commissioning and building a series of walls and fortifications around the city to dissuade any future wanderers from tampering with it. Slowly, the armies withdrew, destroying and sealing all remaining entrances and paths from the Outer Nations into Draconia.
The Great Warriors revealed their deception to the leaders of the Alliance. The Emperor declared that he would place the Shield of Mythos in his Grand Cathedral, ensuring it would always be watched and protected. The Longbow of Teilen would be gifted to the Order of Teilen, who would protect it in their temples, hidden in the forests of Oak's Heart. The Greatstaff of Eval'Gaorv was taken by the Dwarven Queen, to be locked away in the Royal Vaults, preventing anyone from stealing it. The wielder of the Greatsword of D'vorak opted to not attend this meeting, instead sneaking away from the party to search for her husband's remains in the ebony deserts of Tempest.
Since weathering three invasions now, the Dwarves slowly withdrew from the battle-scarred and wasted lands of the North, fortifying themselves with their current borders. Not long after the war was over, the Elves declared Tempest unfit for habitation, and withdrew aid back to their own borders. While Merentha attempted to assist the fallen Nation of Tempest, they were unable to make much headway. 160 years later, after a violent uprising and resulting civil war, the Empire was shattered in three, with the Principality of Jaggonath claiming the central lands of the Empire, and the Shield of Mythos, the newly formed Republic of Asmody claiming the Northern lands, and the remaining inhabitants of the Tempest ruins declaring themselves "free" from oppressive governments, turning the wastes into a lawless quagmire.