The orc-mage bellowed in rage, swinging down his battleaxe. Gunthar, in a well practiced slash, cut the orc in half. Deprived of leverage the body swung backwards as the axe continued its arc down. The legs tottered and fell. Meanwhile Gunthar's companion was cut down by the evil Overlord's left-hand man. Who Gunthar stabbed in the back while they were so occupied. This left the evil Overlord Yosofet and Gunthar as the last men standing. Servant women cowered against the walls, wailing in terror. The air smelled of sweat and blood.
"We can rule together!" screeched Yosofet, backing up and drawing his charmed sword. "Join me and be my apprentice!"
"And why would I do that?" sneered Gunthar, advancing inexorably. The castle was strewn with wreckage and bloody bodies.
"I am wise! I am powerful! But I am old. Alone, I will grind the population of this little kingdom into the dirt a few more years, then die. Together, I can teach you to do more than you could alone! If you learn my secrets, you could rule not just this kingdom, but the whole world! Together, we can ..." and the Overlord swung at the hero.
Their swords clashed. Gunthar leaned in, twisting his sword, knocking the sword out of the Overlord's hands. He pressed the flat of his blade against the Overlord's throat, bringing the edge against his chin.
"I ... accept," said Gunthar, through clenched teeth.
"You ... what?" asked Yosefet.
"That was my plan all along. Why tear up the reins of power, when I can just grab them myself? And I must admit, I have always admired the cruelty of your tactics." Gunthar laughed. "Servant girl! Fetch us some wine, then clean up this mess!"
The nearest servant lifted her hand, level, and turned it slightly, like adjusting a knob. The castle was clean and empty, except for her. The windows no longer had stained glass. The sunlight streamed in. A sparrow flew through. Grass grew in the cracks in the stones. She turned her hand a little more, and she stood on an unpopulated steppe. A whisper of a breeze rustled the stalks of grass, approached and passed, rolling across the plain. It smelled of coming rain. Some scraggly trees were in the distance. She wondered if they were apple trees. She set off on foot to check.
This was in response to a prompt on reddit.com r/WritingPrompts, "'We can rule together! Join me and be my apprentice!' said the evil Overlord to the hero. The Overlord never expected the hero to say yes."