Kirmira was a Rakshasa

Rakshasa

A Rakshasa or alternatively rakshas, is a race of mythological humanoid beings or unrighteous spirit in Hindu and Buddhist religion...

, the brother of Bakasura

Bakasura

Bakasura a great Asura who lived near the city of Ekachakra, and forced the Raja of the place to send him daily a large quantity of provisions, which he devoured, and not only the provisions, but the men who carried them...

, and a good friend of Hidimba

Hidimba

In the Mahābhārata, Hidimba was a rakshasa, the brother of Hidimbi and a forest dweller. He and his sister, Hidimbi were tempted at the sight of the Pandavas and wished to eat them. For this purpose Hidimbi changed herself into a beautiful woman and brought him near Hidimba...

. He lived in the forest of Kamyaka, and used to terrorize the Rishi

Rishi

Rishi denotes the composers of Vedic hymns. However, according to post-Vedic tradition, the rishi is a "seer" to whom the Vedas were "originally revealed" through states of higher consciousness. The rishis were prominent when Vedic Hinduism took shape, as far back as some three thousand years...

s who inhabited that forest. He ran into the Pandava

Pandava

In the Hindu epic Mahābhārata, the Pandava are the five acknowledged sons of Pandu , by his two wives Kunti and Madri. Their names are Yudhisthira, Bhima, Arjuna, Nakula and Sahadeva. Although, Karna is told by Lord Krishna that according to the laws and ethics he is the first son of Kunti making...

s when they began their exile in the Kamyaka forest. Upon learning that Bhima

Bhima

In the Mahābhārata, Bhima is one of the central characters of Mahabharata and the second of the Pandava brothers...

 was present, who had slain his brother Bakasura, the Rakshasa then challenged the Pandava to fight. After a fierce battle, Bhima

Bhima

In the Mahābhārata, Bhima is one of the central characters of Mahabharata and the second of the Pandava brothers...

choked Kirmira to death. (Mahabharata, Book III: Varna Parva, Section 11).