"Duke Gaul. We have acquired the item that you have sought for..." Assassins dressed in all black entered the duke's office.
"It's been a pleasure doing business with the Dark Guild..." Gaul eagerly looked at the energetic mushroom tightly held within the assassin's palms.
Duke Gaul wasted no time in consuming the white mushroom in front of the Dark Guild and his most trusted knights. A booming laughter came from his large physique as an unexplainable energy radiated from his body. The large noble's body slowly floated into the air without the use of magic. As he was feeling the changes going through his body, he suddenly stared at the Dark Guild.
"You may leave." He told them as he floated back to the ground.
"It has been our pleasure to do business with you as well..." The Dark Guild assassins left without a trace as Duke Gaul began to plan his rise to more power.
Time passed with the duke secretly expanding his power base through the usage of his new power. It wasn't until one day that the duke's plans suddenly took a change in nature and direction. Out of the blue, Duke Gaul heard an unfamiliar feminine voice in his head. That voice startled him and innately invoked a reaction of rejection within him. Unfortunately, it wasn't his choice to reject or accept. His every action was now under her control.
And she wanted him to help expand her control throughout the world. Initially, Duke Gaul held massive reservations about having his body and mind invaded like this by some filthy monster, but as time went on, he realized that he could still accomplish his ambitions even if he was forced to become a traitor to humanity. The alluring temptress of a monster that appeared in his dreams at night had him collect several mushrooms in a strange impenetrable fortress deep within Astoria's Forest.
It was a fortress made entirely of living mushrooms that was defended by ferocious, deadly monsters. On each visit, he witnessed the extensive growth of the budding kingdom. More and more creatures inhabited the fortress. It frightened him just how quickly this monster had grown. Maybe it was the right choice to turn against humanity...
"How could we defeat a monster of such proportions?" Duke Gaul felt sorry for humanity.
It granted power at the cost of freedom. It granted safety at the cost of freedom. It even unlocked the natural limits of those under its rule. Only the mentally ill or insanely privileged would turn down such an offer. Most of those under her control didn't even get the choice to turn down her offer, not that they would if they knew of the benefits that it granted.
Duke Gaul may have played a small part in that, after all. He may or may not have invertedly fed those in his territory some of the Overlord's more harmless mushrooms. They may or may not have known he was doing such a thing. It also could be a possibility that his land has significantly grown in strength and prosperity compared to other nobles around him. All suspicions and whatnot. Nothing that anybody could prove anyway. Detecting the Overlord's control was impossible through magic or any other means, but that didn't mean it was impossible to notice. If, one day, a small starving boy living in the slums suddenly becomes taller, fuller, and capable of accomplishing impressive feats of strength or magic. It's likely that he's eaten a magic mushroom.
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"No more mushrooms!" King Avery announced to all corners of his nation.
"Destroy every mushroom and those that eat them." Lord Deathmaw commanded to his undead army.
"The Mushroom Queen and her ilk must be exterminated." Elf Queen Sylvia ordered.
"We are at war with all those that are of Mushroom kind!" Dwarf King Bodak shouted.
"Let the drums of war drown out the whispering spores! Crush the fungi underfoot, my orc brethren! Mushroom expansion ends here – in a sea of orcish strength!" Orc Warchief Gromrak the Slayer yelled.
"Burn the mushrooms, dismantle their machines! Goblins, unleash your chaos upon the fungus-infested lands. Mushroom Queen's tendrils shall wither in the wake of goblin ingenuity!" Goblin Overlord Sprocket screamed.
"Fungi, meet your doom! Let the trolls trample and tear through the stupid plants. Grothak commands, and the mushroom menace crumbles!" Troll Warlord Grothak bellowed.
"Arrows shall blot out the sun, centaurs! Aim true and pierce the heart of the fungal blight. Our hooves thunder against the creeping menace – The Mushroom Queen's grasp loosens!" Centaur Chieftain Swiftwind harrumphed.
"Rise from the depths, my merfolk! Let our waters cleanse the world of this fungal corruption. With magic and tridents, we drown the mushrooms in the abyss!" Merfolk Queen Serenia bubbled.
"From dragonfire, let the fungus be purged! Draconians, soar with flames and scorch the tainted earth. Doom's spores shall find no sanctuary!" Draconian Sovereign Pyraxia roared.
"Flutter on wings of justice, fairies! Our magic shall unravel the fungal threads. Fae rise against the mushroom tide, and with nature's wrath, we prevail!" Fae Monarch Thistledown Wildfire screeched.
Doom's expansion to spread herself all over the world was far too quick and invasive for those in power to take it lightly. King Avery's rule over the nation Salona was forced to split between two kingdoms. Humanity and Mushroom kind fought for control over Salona. King Avery wasn't the only ruler having troubles because of Doom. Doom fought openly and secretly with those under her control.
She formed armies that actively attacked and sought to take land from their enemies while at the same time weakening them from the inside with those under her control before the world knew of her existence. All except the undead army, who were immune to the effects of her mushroom on the account of them being dead. It was their cold, barren lands that she focused a majority of her forces. They required no sustenance and could fight till their bodies decayed in several decades. It was Lord Deathmaw's army that posed the second biggest threat to Doom. But just because they were a threat didn't mean that Doom was worried. Dead things were nothing but a feast to mushrooms like herself.
As long as life was living on this planet, so would she.