Manyu sukta is hymn

Hymn

A hymn is a type of song, usually religious, specifically written for the purpose of praise, adoration or prayer, and typically addressed to a deity or deities, or to a prominent figure or personification...

 10.83 and 10.84 from the Rig veda. It contains 14 verses and is dedicated to Manyu

Manyu

, Vedic Sanskrit for "spirit, temper, ardour, passion, anger" is war god,wielder of thunder,slayer of foes,of Dasyus. He is fierce,queller of the foe and is self-existent. He is beseeched to bring health and wealth...

. Manyu in Vedic sanskrit

Vedic Sanskrit

Vedic Sanskrit is an old Indo-Aryan language. It is an archaic form of Sanskrit, an early descendant of Proto-Indo-Iranian. It is closely related to Avestan, the oldest preserved Iranian language...

 stands for temper, anger or passion. The original deity that this hymn addresses is believed to be Lord Narasimha

Narasimha

Narasimha or Nrusimha , also spelt as Narasingh and Narasingha, whose name literally translates from Sanskrit as "Man-lion", is an avatar of Vishnu described in the Puranas, Upanishads and other ancient religious texts of Hinduism...

.

Identification of Manyu with Rudra(Rudra means Lord Narayana, as Shiva's Bimba Roopa Paramatma is Lord Narasimha)

Satapatha Brahmana IX-1-1-6 says :

"From Prajapati

Prajapati

In Hinduism, Prajapati "lord of creatures" is a Hindu deity presiding over procreation, and protector of life. He appears as a creator deity or supreme God Viswakarma Vedic deities in RV 10 and in Brahmana literature...

, when he had become enfeebled, the deities departed. Only one god, Manyu

Manyu

, Vedic Sanskrit for "spirit, temper, ardour, passion, anger" is war god,wielder of thunder,slayer of foes,of Dasyus. He is fierce,queller of the foe and is self-existent. He is beseeched to bring health and wealth...

, did not leave him, but continued extended within him. He (Prajapati) wept. The tears which fell from him remained in that 'Manyu'. He became Rudra

Rudra

' is a Rigvedic God, associated with wind or storm, and the hunt. The name has been translated as "The Roarer", or "The Howler"....

 with a hundred heads, a hundred eyes, and a hundred quivers. Then the other drops which fell from him in unnumbered thousands entered into these worlds.They were called Rudras

Rudras

Rudras are forms and followers of the god Rudra-Shiva and make eleven of the Thirty-three gods in the Hindu pantheon. They are at times identified with the Maruts - sons of Rudra; while at other times, considered distinct from them.-Birth and names:...

 because they sprang from him when he had wept. This Rudra

Rudra

' is a Rigvedic God, associated with wind or storm, and the hunt. The name has been translated as "The Roarer", or "The Howler"....

 with a thousand heads, eyes, and quivers, stood with his bow strung,and arrows on the string, causing terror, and demanding food. The gods were afraid of him. They said to Prajapati,:'We are afraid of this being, lest he destroy us.' Prajapati

Prajapati

In Hinduism, Prajapati "lord of creatures" is a Hindu deity presiding over procreation, and protector of life. He appears as a creator deity or supreme God Viswakarma Vedic deities in RV 10 and in Brahmana literature...

 said to them: 'Collect for him food, and with it appease him.' They collected for him this food, the satarudriya."

Later, all gods,including Prajapati

Prajapati

In Hinduism, Prajapati "lord of creatures" is a Hindu deity presiding over procreation, and protector of life. He appears as a creator deity or supreme God Viswakarma Vedic deities in RV 10 and in Brahmana literature...

 sang Satarudriya hymns and appeased Rudra

Rudra

' is a Rigvedic God, associated with wind or storm, and the hunt. The name has been translated as "The Roarer", or "The Howler"....

. Satarudriyam begin with the words : "Namaste Rudra Manyava..... ( Salutations to thy anger O Rudra.... )