He was the son of the king Purukutsa and grandson of the famous emperor Māndhātṛ of the solar race. He got this name since the dasyus (robbers and enemies) used to quake in fear (tras = to be afraid) before him. Once the sage Agastya approached him for money. Since he did not have it at that time, he suggested that the sage, along with two more kings—Śrutarva and Bradhnāśva, who had come with him—approach Ilvala, a rich and powerful dānava (belonging to the race of demons).
When Agastya met him, Ilvala realised his greatness and gave him all the money he needed.