Alternate Universe

Erm...I've interrupted my "monk week" to post this, but it's important. In Creative Writing, my teacher, Mr. Dowdle, assigned us to create our own world or alternate universe. I need opinions ensuring that my structure is original and capable of usage for a short story. Comment with your opinions! :)

• Shadows are dangerous and deceitful
• Dark = security & light = place of fear (reversing the usual pure vs. evil symbolism)
• Shadows can think, feel, and act
• Shadows commit crimes and the host is found guilty
• The shadows are incapable of any/everything when they can't exist. (in the dark)

In my world, shadows are dangerous and deceitful. Dark becomes a place of security while the light is feared. The more time that shadows spend in existence (or in the light because that’s the only way they can exist) the more time they have to plot what they are going to do to ruin their host. The shadows are generally evil and only a specific group of people have shadows that have the ability to leave them, think, and feel. Besides the group of people whose shadows can leave them, the rest of society is unaware of the possibility. When a shadow leaves its host, it uses their silhouette to their advantage to create problems for the host. (i.e.: the shadow robs a bank, but the person to whom the shadow belonged to is arrested.) The groups who are limited by their shadows are people who have committed an unforgivable crime involving the creation or destruction of a human life