It Has Already Begun.
The Great Mushroom War did not begin when one of the Old World Human kingdoms launched its weapons. It did not begin when the atom bomb was fully constructed. It did not begin even when the idea of a weapon of such destructive power was conceived.
It began when the Professor laid waste to the King and his dark subjects. The War began when the demons of the Old World Era showed weakness to Humanity.
When the Professor defeated the King atop his own castle, he laid the seed that would grow into the tree that gives power to the Humans.
The Professor drove his sharpened wooden stake through the King's dead heart, sealing the vampire into the coffin in which his essence would lay for eternity. This was a lie.
"History is written by the victor," yes? The King's apparent fate was written as fact by the Professor himself. The stake did not go through his dark heart – rather it was driven next to it. Through the middle of the King's chest, intentionally. The Professor is a scientist, after all, and he needed a test subject. He needed living proof that the Underworlds did exist and he believed fully that the Vampire King was his key.
They Have Already Lost.
The King was brought forth in front a crowd of thousands. Eager to see a real monster, hordes of upper class citizens from all over the Ancient Human Kingdoms arrived in swathes to see the beast. Mercifully, the Professor removed the King from his coffin once the Sun's light dipped under the horizon. The Professor does have a crowd to please, and please he will.
In his mind, the King worked over plan after plan. All ended in failure. His bounds were too tight, laced with too much silver, and sprinkled with too much garlic. His body was raised above a body of water, held together inside a barrel that was an elephant wide.
To his surprise - and to the Humans' surprise - the Professor motioned for another coffin to be opened.
It was the King's first lover - before his brides. She was brought forth from her prison and forced to kneel before the thousands. The King began to squirm against his bonds. The tears that were held back for centuries finally flowed.
He watched as the Professor drove his god forsaken stake through her undead heart and his tears stained the ragged shirt he was allowed to wear. As the thousands gasped at the spectacle, the Professor turned towards the King, his eyes filled not of pride, but of sorrow.
As the King's lover began fading into dust, he heard the Professor say those blasted words: "It must be this way. Light and Dark cannot coexist together as one."
But We Are Still Together.
"However, Light and Dark must exist separately to keep balance to our world. Become our guardians of the night," the Professor added. He was talking to a small crowd of young vampires, all looking eager to be part of the Professor's plan. "We give you pure Human blood, and you give us your might."
The Professor turn towards his partner, who was seated next to him, eyes downcast and shadowed.
"Your Grace? Anything you might add?" he asked with a tiny smile.
The King raised his head, lost in thought. Finally, he uttered a single word.
"No."
As the class left, the King began to mull over the very same plans he had created when his first lover was vanquished. Once again, all ended in failure. The Covens would be destroyed, the Were-beasts subjugated, and the Spirit Worlds controlled.
The Sanguine Bloodlines?
Allied with the Humans as they conquer the galaxy.