Ajāta (Ajaata) was one of the ten sons of Ṝidika (Hridik) of the  Yadu-Vṛṣṇi (Vrishni) clan. He sired three powerful sons — Sudaṃṣṭra (Sudangshtra), Sunābha (Sunava) and Kṛṣṇa (Krishna).

Matsyapurāṇa(44.82-84)