The Dark Gemstone.

Zeratos paused to recall the things that had transpired which brought him to his current state. He had once been human. A ruthless, powerful warrior whose ferocity on the battlefield was legendary. Entire armies feared his wrath.

He got along better with the monsters of the world than he did with other humans. Steadily he fought more and more alongside the monsters. Eventually they turned him into one. He quickly rose through their ranks and became their king. Then he waged war on humanity and conquered kingdoms, countries, and entire continents. Heroes chosen by the gods rose up to stop him, but he slaughtered them all. When almost all the humans of the world became slaves to demons, the gods stepped in to save them. But even they fell before his ever increasing might.

He stole power from everything. Objects, people, demons, heroes, and even the gods. He became all-powerful and ruled the world with an iron fist.

He soon gained the power to travel to other worlds. He used this power to invade and conquer one world after another. His foes were weak and their resistance was pitiful, but they did amuse him. And the spoils of victory were wonderful.

Eventually the worlds he hadn't conquered yet rallied and the ones he had rebelled. They formed massive armies that were led by the most powerful beings in the universe. He tore through them like they were nothing. Only the most powerful ones could withstand his might for more than an instant. Even with their combined forces, they had no way to destroy him. It was laughable.

Then they changed their tactics. Rather than trying to kill him, they resorted to trapping him within a jewel. It was a desperate, last-ditch attempt to stop him, but it worked. He was now trapped within a large jewel that he could not escape from. The only way out was for someone on the outside to break the jewel.

Zeratos had so many followers that would've gone to any lengths to free him that he should've been out within the hour at most. But these people weren't fools. They took that jewel and fled. They crossed many worlds, covered their tracks and created decoys to ensure that he would never be found. He was permanently separated from his worlds, his 25 wives, his 72 children, his castles, his forces, his massive harem of over 400, his treasures, his allies, his hard won trophies, and everything else he enjoyed in life.

And if that wasn't bad enough, it happened right before the annual festival done in his honour. He loved that festival and so did everyone else. It was like Mardi Gras, but there was also competitions with female gladiators fighting nude so they could rape their defeated opponents in front of the crowd and claim them as their slaves for a week afterwards. It was glorious.

He didn't know how long he was trapped in there, as all sense of time was lost and what felt like twenty years could actually be a few months. But during his time in there he devised a plan of escape. By gradually expelling the evil energy that drove him to become the demon king and slowly channelling it into the jewel, he was eventually able to corrupt it, then bring it to life and take control of it. He still couldn't escape, but he could move it around and do other things that weren't an option before.

The jewel transformed. Its colors went from light blue to dark purple. Its shape went from flawlessly round to more of a classic diamond shape. From the bottom, octopus-like tentacles sprouted, granting him mobility. It became slightly larger than a football, (enormous by gem standards, but small enough to transport and hide easily.) And then a single, large eye appeared at the front. He could now see and hear everything outside of his prison and move it anywhere he wanted.

Now was the time to regain his former glory. He would use his new power to start a war with everyone he could find, they'd retaliate and destroy the jewel, and that would free him and allow him to return to his old life.

As he had suspected, he was at the bottom of the ocean. It took a lot of swimming to rise to the surface, but then he found himself stopped by a thick layer of ice. It seemed that to further stop any rescue attempts he had been dropped at either the north or south pole. He could only guess which one.

Navigating while underwater wasn't his strong point. Swimming around in total darkness while trying to find a way out would take too long. So he charged up the crystal and fired a laser from its eye. The laser melted and cut through what seemed like miles of ice before he made it out.

Zeratos was expecting the place to be a barren wasteland in the middle of a snowstorm. But instead it was clear out and there was a city made of ice nearby. Going in to investigate and get some answers, he tried to stay out of sight. He needed information more than he desired chaos.

Considering his options he thought it would be easiest to just kidnap a girl and have her tell him everything he wants. After all, there was no way of knowing if he'd be able to read their writing, and stalking people just to eavesdrop would probably only yield local gossip. Asking people seemed a far better idea.

He looked around until he spotted one that caught his eye. She was young, beautiful and had white hair. Judging by the number of people around her, he guessed she was some kind of royalty. He remained out of sight as he followed her at a distance.

She entered a tower that he couldn't enter without being spotted. Not via the door anyway. He flew up and snuck in through a window. In there was a bath fit for royalty.

He heard voices right outside, so he thought it best to wait for her to show up, rather than rushing out and causing a panic. It wasn't a long wait as she came right in, shut the door, stripped naked and got in the bath. Zeratos got a full view of her luscious nude body as she cleaned herself.

"This feels so good," she said as she washed her privates.

"And things are about to get even better."

Then he fired a purple beam that encompassed her body and shattered it into orbs that were sucked inside the jewel. Then he flew out of there before anyone else came around.

She reformed inside the jewel, looking exactly like she did before. Even the soap and water clinging to her body were in the same place.

"Where am I? How'd I get here?"

"Welcome, to my home."

She turned to see a large man with dark purple skin, four arms, glowing white eyes, spiky glowing white hair, giant muscles, surrounded by a dark aura and wearing only a loincloth. He was an intimidating sight to behold.

She panicked, covered herself up and screamed. The next thing she knew a strange force picked her up, spread out her arms and legs, and carried her through the air to him.

She was terrified. Her surprisingly well-developed body was on full display and she was powerless to do anything. This demonic man could do everything he wanted to her and she had the feeling he wasn't going to wait around to do it.

"Hello. My name is Zeratos. And who might you be?" he asked as he grabbed and fondled her breasts and pussy.

"M-m-m-my name is princess Yue. Please let me go!"

"No, I think you'll do for a fine start. Now tell me everything you know of this world."

He channelled his powers into her, corrupting her and taking control of her mind. She was unable to resist as her will was shattered and she now saw him as her glorious new master.

Yue had been raised in isolation, so her knowledge was limited. But she hadn't been living under a rock without even knowing there was an outside either, so she had more than enough good information for him to work with.

Said good information came to a temporary halt as he gave in to his pent up lust and shoved his dick down her throat. She bobbed her head up and down on it until he shot his first load. She tried to swallow as much as she could, but there was enough to fill a bucket so she ended up coking, coughing and gasping for air.

"One hole and one shot down. Two more holes and several hundred shots to go," he said as she struggled to handle the first load.

He bent her over and lined his cock up to her pussy. Then he thrusted it in and she cried out as he destroyed her hymen and stretched out her unused pussy. He stayed still for a minute to let her get accustomed to her size, then he began thrusting.

He spent an entire week raping her. He stretched out her pussy and ass into gaping holes, and filled her with so much cum that her stomach stretched out enough to make it seem like she was about to give birth. She was fucked until she died, then he revived her and restored her form to do it all over again. And again, and again.

After a week of nonstop sex his lust had been quenched just barely enough for him to look for more girls. But searching Yue's mind turned up nothing but sex, so he just resumed control of the jewel and went on his way.

Author's Note: My plan for this story was to have Zeratos abduct hot female characters and attack whatever or whoever he could find, driving others to go all out in their efforts to destroy him. But the jewel would prove too hard to break, resulting his victory. So he'd flee to another world to try again there. Then it'd be rinse and repeat in other worlds, with different girls and different opponents. And he can draw in more than just women. He can draw treasure, objects, buildings, even a tropical island with part of the ocean included. But it's a one-way trip, so he's a bit picky about what he adds. Eventually he creates a small kingdom within the jewel where he lives like a god with a gargantuan harem.

(In case you couldn't tell, this first world is Avatar: The last Airbender.)