He was the preceptor (upajjhāya) of Vaṅgīsa, and together they lived in Aggāḷava-cetiya (S.i.185), where Nigrodha Kappa died. When Vaṅgīsa questioned the Buddha as to the destiny of Kappa, the Buddha’s answer was that he had completely passed away (Thag.vs.1263 ff; SN.vs.343 ff). It is said (ThagA.ii.211; SNA.i.346) that Vaṅgīsa was away when Kappa died, and had also seen him sleeping with his hands curled up. This was unlike an Arahant — one who had destroyed the corruptions (khīṇāsava), but, in Kappa’s case, it was due to a long-continued habit. Vaṅgīsa, not knowing this, was assailed with doubts as to his teacher’s attainments. Kappa attached importance to keeping to his cell. When he came back from his almsround, he would enter his cell and not leave it again until evening or the next day. This caused disaffection in Vaṅgīsa’s heart, which the latter quelled by force of reasoning (S.i.186; SA.i.208).

Kappa was the thera’s personal name, but the prefix Nigrodha was given because he attained Arahantship at the foot of a nigrodha (banyan) tree (SNA.i.346). It was because he dwelt under a banyan, says SA.i.207.