Nitya Siddhi Jiva is ever-free being in Visishtadvaita in Hinduism and it is also part of philosophy of Jainism. The concept belongs to one of the categories of free souls. Jainism and Visishtadvaita classify jivas or souls into three groups – mukta jivas or liberated souls, baddha jivas or bound souls, and nitya siddha jivas or the ever free and perfect souls.
The liberated souls have achieved freedom from karma (effect of deeds), while the bound souls are caught up in the cycle of birth and death due to the efficacy of karma.
The nitya siddha jiva possesses chetana (pure consciousness), which is the essence of the soul. It is eternal, having the character of jnana (perfect knowledge) and avyavadha (equanimity). Having infinite knowledge, according to Jainism, there is nothing in the lokakasha (filled space) or the alokakasha (void space) that is beyond the cognition of the self. Due to infinite darshana (perception), its omniscience reveals all the things of the universe, past, present and future, in all their infinite qualities, modes and aspects. Omniscient knowledge is unlimited, infinite. The soul, not being attached to matter, is characterized by formlessness. So it is possible for many such souls to exist in the same place.
According to Vaishnava Visishtadvaita philosophy, Ananta, Garuda, Vishwaksena, etc., are nityajivas who never fall into the bondage of the world and dwell in Vaikuntha, having divine bodies of pure sattva in the sannidhya (proximity) of Bhagavan Vishnu.
The nitya siddha being is omnipotent, having infinite power (virya). Nitya siddhi constitutes a state of absolute perfection. Apprehension and comprehension are developed to the full extent and are considered to be identical with each other. It is a state of uninterrupted, interminable, inexpressible tranquility, which is fully explicit in the soul. Ever free emancipation is that state wherein the soul exists, transcending limits of space and time, in a state of eternal bliss.