alpha

(fictional). A person, usually a man, with the secondary gender alpha. Alphas are capable of impregnating male omegas, and are usually primarily attracted to omegas of the same gender

Depending on the work, alphas may also have a number of other non-standard traits including scent glands, knots and ruts

The alpha stepped towards the omega, his pupils dilated "you are in heat" he growled.