Hanuman is the incarnation of the tenth Rudra or part of Lord Shiva, who is said to have eleven Rudras in all. He was born to Kesari, the king of monkeys, and Anjana. As the son of Anjana, Hanuman is also known as Anjaneya. He is god incarnate of might and mind.
During the Rama–Ravana Lanka yudh or war, Hanuman assumed his panchamukhi or five-faced form to kill Ahiravana, a powerful demon, a black magician, and possessor of a mysterious weapon, the nagapasha, darts that would secretly inject serpent poison into human body. Ahiravana, the brother of Ravana, had taken Rama and Lakshmana to the netherworld as captives while the two were sleeping at night.
The only way to kill Ahiravana was to extinguish the five lamps lit up in five different directions, all at the same instant. To accomplish this almost impossible task, Hanuman assumed a panchamukhi form and blew out the lamps in one go. Rakshasa Ahiravana was killed and thus, Hanuman freed Rama and Lakshmana.
The five faces of Hanuman are that of an eagle, Garuda, facing the west; a boar, Varaha, facing the north; a horse, Hayagriva, facing the sky; a lion, Narasimha, facing the south; and the fifth being the original Hanuman, facing the east. The panchamukhi Hanuman has ten arms holding ten different weapons, including his own celebrated weapon, the gada.