Buddhaghosa says ¹ that both his parents were Nigaṇṭhā, skilled debaters, who married at the suggestion of the Licchavī, because they were unable to defeat each other in argument. The Licchavī provided for their maintenance. Four daughters were born to them: Saccā, Paṭācārā, Lola, and Sivāvatikā. These engaged in a discussion with Sāriputta, and were defeated by him. Having then entered the Order, they became Arahants. Saccaka was their brother and was the youngest of them. He was a teacher of the Licchavī and lived at Vesāli.
When Saccaka was defeated by the Buddha as stated in the Cūḷasaccaka Sutta, one of the Licchavī, Dummukha, compared him to a crab in a pool, its claws being smashed one after the other and unable to return to the pool. Saccaka, admitted defeat, and begged the Buddha to take a meal at his house. The Buddha agreed, and Saccaka became his follower (M.i.234 f).
It is said (MA.i.469 f) that, in a later birth, long after the Buddha’s death, Saccaka was born in Sri Lanka as the Thera Kāḷa-
Saccaka is identified with Senaka of the Umaṅga Jātaka. J.vi.478.
¹ MA.i.450; cf. J.iii.1, where Sivāvatikā is called Avavādakā.