Kaundinya was one of Sakyamuni’s original disciples who followed him when he first gave up his princely throne and set forth on the quest for enlightenment. There had been five of them, and together with their master they had performed arduous ascetic practices (practices which Sakyamuni later said were useless). After the Buddha attained enlightenment, these five ascetics became his first disciples.
Others of the five hundred arhats included Uruvilva-Kasyapa, Gaya-Kasyapa, Nadi-Kasyapa, and Aniruddha. The first three arhats were three of the Kasyapa brothers, who had once been leaders of a group of fire-worshippers. It is said that originally these brothers had bitterly opposed Sakyamuni, and had used supernatural powers to discredit him. They were defeated, however, and they together with most of their followers became loyal disciples of the Buddha. Aniruddha, another of the arhats mentioned, was a cousin of Sakyamuni. He was famous for his clairvoyance, the alleged power of seeing beyond the natural range of the senses. It is said that during his early days of severe ascetic practices, he went blind. In place of his natural sight, he developed clairvoyance.
Introduction to the Lotus Sutra