Vishnu’s seventh incarnation is Yajna (Yajna means fire rituals). He was born to Aakūti (aakuti is the oblations offered into fire in a fire ritual) and Ruchi and performed a number of yajnas. Ruchi was holding the post of Indra during Swayambhuva manvantra, the first of 14 manvatras. (Bhagavata I.3.10)

His eighth incarnation was Riśabadeva. It is said to be a partial incarnation. He was born to Nabhi and his wife Meru Devi. Nabhi transferred the responsibilities of administering his kingdom to Riśabadeva. After knowing his greatness and out of jealousy, Indra stopped rain to his kingdom. But Riśabadeva brought abundant rainfall through his yogic powers. Finally, he left his body through a forest fire in Coorg Mountains. He led a typical life of a Paramahamsa (it literally means the great swan. It is an epithet of knower of Brahman whose soul sports like a swan in placid ocean of Pure consciousness and eternal bliss.) (Narayaneeyam: Canto 20)

His ninth avatar was Prithu. There was a king by name Anga. He had an evil son by name Vena. Anga upset over his son’s behavior went to forest to meditate on Vishnu. Vena was crowned as the king. He abused sages who advised him to pursue virtuous path. Sages cursed him and he died after a month (it must be remembered that curses from ordinary persons are also powerful and are capable of causing miseries). His body was preserved. As there was no king to administer the kingdom, the sages churned up his thighs and arms of his body and made the body sinless. While they were churning the body’s hands, there appeared King Prithu, another incarnation of Vishnu. He did all auspicious things to his kingdom. During this incarnation of Prithu, He met Sanaka kumaras. As taught by sage Sanaka, He went to forest for further spiritual pursuits. (Narayaneeyam: Canto 18)

His tenth incarnation was Matsya avatar. When there was pralaya (annihilation) at the end of sixth manvantra, Brahma was in deep sleep. There was a demon by name Hayagriva (different from the Hayagriva form of Vishnu) who stole all the Vedas from the mind and memory of Lord Brahma. Vishnu took the form of a fish (matsya) to save the Vedas. (Narayaneeyam: Canto 32)

His eleventh avatar was Kūrma (tortoise). When the gods and demons began churning the ocean with Mount Mandara using serpent Vasuki as the churning string, Vishnu assumed the form of a tortoise and supported the Mount Mandara on His back. (Bhagavata I.3.16)

His twelfth incarnation was Dhanvantari. During the process of churning Goddess Lakshmi, the consort of Vishnu emerged. Then inebriating liquor, the source of sin and vice gushed out. Finally, there appeared Dhanvantri with excellent complexion carrying in his hand a pot of ambrosia. (Narayaneeyam: Canto 28)

His thirteenth avatar was Mohini (temptress). When Dhanvantri brought ambrosia, the demons took the pot from Him. Suddenly Dhanvantri disappeared. Due to Vishnu’s maya, there arose a quarrel amongst the demons. When the demons were fighting there appeared a beautiful young woman. On seeing this woman (Mohini avatar) the demons stopped their fight and asked Mohini whether she could distribute the ambrosia amongst them. When she agreed, the demons handed over the pot containing the ambrosia to her. In the melee, ambrosia was given to gods. Shiva became curious to see Vishnu’s Mohini form. It is said that the conqueror of Cupid Shiva lost his mental balance for a moment on seeing the beauty of Mohini. (Narayaneeyam: Canto 29)

His fourteenth Avatar is Narasimha avatar, whose form is widely worshipped. In Varaha avatar, Vishnu killed the demon Hiranyākśā. His brother Hiranyaksipu deeply grieved by the death of his brother vowed to destroy Vishnu. He did tapas and got a boon from Brahma that would not be killed by any gods, humans and beasts. After having obtained this boon, he conquered Indra and reached Vaikuntha. Vishnu made Himself into a subtle form and entered the heart of Hiranyaksipu. After failing to find Narayana, Hiranyakasipu was under the impression that fearing him, Vishnu had ran away. The demon returned to his kingdom. Prahalada was born to him and became a great devotee of Vishnu. Hiranyakasipu tried all means to prevent Prahalada from being a devotee of Vishnu but he miserably failed. He then decided to eliminate Prahalada, but again Hiranyaksipu failed. Deeply disconcerted with Prahalada’s behaviour, one day Hiranyakasipu asked Prahalada who supports him. Prahalada replied by saying that Vishnu is the supporter of everything including Hiranyakasipu. Challenging his son, Hiranyakasipu struck a huge pillar with his mighty sword. There was a noise much louder than a thunder. By ripping open the pillar there appeared a form that was neither a god nor a human nor a beast. His body looked that of a human and his face and hands resembled a lion. This was the form of Narasimha (nara – human; simha- lion). Lord Narasimha put Hiranyakasipu on his lap tear open his chest by roaring like a lion. His roarings rattled all the worlds. Everyone was scared to go anywhere near Narasimha. But, Prahalada prostrated before Narasimha and by whose love, Lord Narasimha cooled down and vanished. (Narayaneeyam: Canto 25) This incarnation is said to be of shortest duration. There are two Upanishads for this incarnation. They are Nrisimha Pūrvathāpini Upaniśad and Nrisimha Utharathāpini Upansihad. Nrisimha mantra beginning with ‘ugram vīram mahā viśnuṃ’ is known as Mantra Raja, which means the king of all mantras or the superior mantra. There are 32 letters in this mantra and each of these letters represents one god. There are specific ways of reciting this mantra rajam in combination with certain other mantras which eradicates all miseries (Nrisimhathapani Upanishads)