Medieval/fantasy or Modern/fantasy

Long ago, a great darkness ruled the lands, enslaving the people as the lands began to decay. The ruler was a feared overlord, a man so powerful that man of those enslaved saw him as a god. During the years of his rule, rebellious factions sprung up, daring to challenge him. And each time, he snuffed them out, except for the last group.

The small faction of mages and warriors were able to overpower him, the mages having discovered a powerful magic. And by using the power held within a single conduit, were able to defeat him, but they were unable to kill him. So, the decided to lock him away, and split his power into six orbs. Though the overload was prepared for this, he would live forever until someone loyal released him, or until his escape. Though the magic on the seal began to slowly fade over time.

And that was when he made his escape. Once more his terror would reign, his armies forming as he slowly began building his power once more.m. He would find his orbs, and would shroud the world in darkness once more.

Medieval/Fantasy

Magic was a powerful thing, it brought forth new creations, new inventions. Air ships roamed the skies, while large crystals powered intricate looking trains. Though everything else was much like it had been for nearly one thousand years. With magic, they didn't see the need to focus on science, though there were some people who delved into the arts of alchemy and mathematics. Though the lands seemed peaceful, that was far from the truth.

Far to the north, a king sought the lands, wanted it all for himself. Those he ruled lived in poverty, only the nobles and those who pledged allegiance to him lived comfortably. His armies easily crushed those he came upon, and people fled further and further south. However, it was said that during a time of great need that two heroes would emerge, and that they would be able to protect those that couldn't protect themselves.

Modern/Fantasy

There is more to the world than many people know or see. Not just humans inhabit the cities and towns, but normal people wouldn’t even notice. There are those who coexist peacefully, and for those who don’t, there are hunters. And for the humans who cause trouble, who make the world dangerous, well, there’s government assassins.

He was one of the best, strong, experienced and he felt he had seen it all in his ten years of work. To him, stories of demons, of vampires and werewolves were fantasy, tales to scare and entertain. But in reality, they weren’t, and what he knew came crashing down around him. One of his targets hadn’t been human, and he wasn’t the only one trailing that monster.

Sci-fi

The government has all but fallen, becoming shattered after attempting to unify under one. The huge city that was once earth is now a playground for the syndicates. Between earth and mars, the floating space colonies met the same fate. The geeening planet of Mars is the only relative safe place. Small cities dot the planet surface, and one acts as the headquarters for a government agency that still stands.

It had been ten years since the government collapse of 2463, and the agency is just now beginning to make a dent thanks to someone they only know as Cyber Witch. The mysterious hacker had been giving them information for a year, raising no alarms as they leave the file on a desktop. With the information, they've been able to stop many syndicate crimes, but one day, a file was left, one asking for help. The hacker had been found.
(I also have a variation where a syndicate leader finds her instead of the government)

Modern/Fantasy (College Classmates)

He didn't believe in demons, ghosts, or anything that dealt with paranormal or fantastical thoughts. He was rooted in the real world or in what he felt was real. Yet, he found himself joining a college classmate in paranormal investigations, and he loved finding logical explanations for things.

But that all changed when he witness an event he couldn't explain. And even more shocking, the girl he does the ghost hunting with is a witch, with a small dragon familiar.

The Demons Bride

In her younger days, she had been a foolish witch, wanting only power. She made a deal, offering her first born child as a bride to a powerful demon lord in exchange for something. The young woman had gotten what she wanted, though several years later she ended up married and soon she had a daughter. Over the years, she began to regret her choice, she shunned magic and refused to even acknowledge it existed or teach her daughter.

It was a few days after the daughters eighteenth birthday, and she had hoped the deal was forgotten, but his appearance at her door told her otherwise. She had never told her child of her deal, and now she had no choice but to.

A Foolish Witch

Summoning magic was one thing tried to avoid, but she still had to practice it. She made sure to study what she was doing carefully, knowing lesser demons would be easier to deal with than anything else. What she didn't expect was the book to be tampered with, and one wrong word led to her summoning a powerful elder demon.

The Halfling and the Demon

The young woman always knew her father was busy with work, and that some days he would be gone for almost a week at a time. But she didn't resent him, and enjoyed the moments she had with him. But one day, the truth was revealed.

Her father had been a powerful demon lord, ruling over a vast amount of land. He had fallen in battle, and as his child, she was expected to take his place. But there was one problem: she had been raised as a human, she didn't know the first thing about ruling or even her demonic abilities. But waking that demonic side was simple, all she had to do was break the locket she wore.