Omegaverse: The Romantic Affairs of Avon & Drake

In this world, there are more than just "male" and "female" genders. There are "Alphas", who make up 19% of the population and are the most elite in the world. There are "Betas", who are the most normal and make up 80%. And then there are "Omegas", who only make up 1% of the population. Both males and females can get pregnant if they are born Omegas. Once a month, Omegas go into a "heat period" where they give off large amounts of pheromones that attracts both Alphas and Betas, who often rape Omegas on sight anyway. Because of this, Omegas usually wear a collar or take special pills that suppress their heat before they go outside. They also have a hard time finding decent jobs and usually have to work as prostitutes to earn money.

And then there's "becoming a pair". When an Alpha bites the nape of the neck of a Beta or Omega (or a Beta biting an Omega) during sexual intercourse, those two are bound to each other and can only have children with their paired partner. Although it doesn't happen very often, sometimes two people find their "fated pair". This is when two people are destined for each other and instantly feel attraction towards each other upon their first encounter. Very few meet their fated pairs during their lifetime, but when they do, they'll know when it's them.