Brahmin sub-castes competed through rival myth-making to assert internal superiority.

Evidence

Here, he is alluding to the mythical Brahmin warrior Parashurama’s twenty-one wars of extermination against the Kshatriyas after Parashurama’s father is killed by a Kshatriya and he sees his mother beating her chest twenty-one times. Mythical and legendary narratives asserting the authority of the Brahmins were in conflict with each other as Brahmin sub-castes tried to establish superiority over one another through competitive myth-making. — Ambedkar, B R, Annihilation of Caste_ The Annotated…, 1130