The nitya-sūris ('eternal wise ones' — from Sanskrit 'nitya,' eternal, and 'sūri,' learned or wise) constitute one of the three principal categories of sentient beings recognized in Viśiṣṭādvaita philosophy, the others being the baddha-jīvas (bound souls in saṃsāra) and mukta-jīvas (liberated souls). The defining characteristic of the nitya-sūri is that they have never been subjected to the bondage of karma and the cycle of birth-death-rebirth. They reside permanently in Śrīvaikuṇṭha, the transcendent abode of Bhagavān, and are in a constant state of direct, unmediated experience of Bhagavān's divine nature (svarūpa), qualities (guṇas), and splendor (vibhūti).
The nitya-sūris perform kaiṅkarya — the selfless, love-motivated service to Bhagavān — as their very nature, not as a means to an end. This is a crucial theological point in Viśiṣṭādvaita: kaiṅkarya is both the intrinsic nature and the fulfillment of the individual ātman, and the nitya-sūris embody this completeness without interruption. Their jñāna (knowledge) and bhakti (devotion) are infinite and unobstructed — they perceive Bhagavān directly, without the veil of avidyā (ignorance) or the distortion of karma. The most celebrated nitya-sūris include Ādiśeṣa (who bears the universe and serves as Bhagavān's couch and canopy), Garuḍa (Bhagavān's mount and devoted servitor), and Viśvaksena (the commander of Bhagavān's celestial army and the lord of the divine retinue). These three are given special prominence in Śrī Vaiṣṇava liturgy and iconography.
In the Divya Prabandham and the rahasyagranthams, the nitya-sūris are invoked as models and objects of aspiration. The Āzhvārs frequently express the longing to join the nitya-sūris in Śrīvaikuṇṭha, and in particular Nammāzhvār's Tiruvāymozhi describes the state of the liberated ātman entering Śrīvaikuṇṭha and being welcomed into the fellowship of the nitya-sūris. Piḷḷai Lokāchārya's Mumukṣuppadi identifies the goal of prapatti not merely as escape from saṃsāra but as participation in the same kaiṅkarya that the nitya-sūris perform, thus placing the aspiring devotee in a continuous fellowship with these eternal beings. The Śrī Vaiṣṇava theological imagination of heaven (Śrīvaikuṇṭha) is thus not a place of passive beatitude but of active, joyful, communal service — the service that the nitya-sūris have been rendering since eternity.