The Alpha Primitives were a slave race created by the Inhumans, an advanced offshoot of humanity. Because of the Inhumans' low population, they created a labor force of hominids bred to be strong, but of limited intelligence. They were also rendered unable to breed, being produced only by cloning.
The scheming usurper Maximus the Mad tried to use the latent guilt most Inhumans felt about the Alphas in one of his many plots to overthrow the royal family of Attilan, utilizing Omega, but the guilt was abolished when the Inhumans' ruler Black Bolt declared the Alpha Primitives free. The Alphas would no longer be cloned, and those already made would be allowed to live out their lives in a preserve under the city proper.
Maximus again tried to use the Alphas in his schemes, mutating three of the creatures into malevolent beings of pure mental energy known as the Trikon, but they were defeated and banished into the Negative Zone.
The remaining Alpha Primitives live quietly in their preserve, many still mindlessly performing the jobs for which they were trained.