This is a world dominated by Alphas comprising 20% population and Omegas comprising 10% population while the others are Beta's.
The secondary gender(Alpha, Beta and Omega) is determined when the children reach teenage unlike their primary gender(Male and female).
In this world Omega's are treated as Submissive creatures whose main duty is to bear children for their partners.
Beta's are considered as work class people or commoners in this world who work under Alpha's.
Though Omega's are considered weak and delicate, their scent can calm and soothe their partner's Hormones and sometimes it makes their partners difficult to resist the urge to mate with them.
These rare and calming Scents with little population make Omega's important to Alpha's and makes them fight among themselves to claim authority on them.
In this process many Omega's undergo abuse and constant misconduct whenever their Hormones act up and they Undergo Heat's.
The Omega's heat cycles sometimes can be very wild as they release a strong scent which makes the Alpha's and Beta's around them go wild and makes them the prey.
Sometimes their Heat is taken advantage of by many Alpha's and even some Beta's. Also having intercourse with an omega calms those Alpha's who are in their Rut and helps them keep their emotional balance.
So to secure and protect their partner's, Alpha's often mark their Omega's with their scents.
Also in every domain Alpha's dominate the fields irrespective of their gender with their strength and intelligence superior to all others.
Soon this superiority began to change into Domination, they didn't let Beta's and Omega's to reach that position and used various means to bring them down.