A Universe of Magic
Everyone in the world has magic, it is breed down through families, and everyone without Magic is executed by the King.
Fantasy
Once upon a time, King Tanek was crowned. During his feast, a witch came to I’m offering a gift. As a fellow magic user, the King listened to what she had to say, and treated her kindly. In return for his kindness, the witch gave Tanek the gift of immortality, and a warning. She warned the young king of his doom. “The one who is your doom will kill you without the use of magic, for they have none.” Scared of this message, the King hunted down all people who didn’t have to gift of magic. He only allowed two people with magic to have children, so they may too have magic. He ruled over the land for thousands of years, letting his fear of death rule is mind.
The technology in this world is generally pretty poor. Being under the same king for a thousand years causes not a lot of progress to be made in terms of tech. The world is set in a kind of medivial times.
Physics are the same as the real world, despite magic existing.
Each person born has a unique magical signature. Some siblings have similar ones. Each person has a specific skill in magic, for example, some magicians focus on elemental magic, or telekinetic magic. All magicians can do all types of magic, but some are naturally more skilled in certain areas of magic.