Alpha is Rem Ayanokōji's pet kitten, serving primarily as a combat support companion. This feline possesses the ability to shift into a larger, ferocious wild cat form during confrontations with dream demons and other supernatural threats within dangerous dream realms. Alpha utilizes this transformation strategically to aid Rem in battles against entities invading human dreams.

The kitten operates alongside Beta, Rem's pet puppy, who transforms into a large wild dog. Together, they provide complementary assistance during Rem's investigations and combat engagements. Alpha demonstrates the capacity to detect and engage hostile supernatural entities, as evidenced by instances where spirits within a victim's bedroom were dispatched upon the kitten's intervention.