Birth of Mahisha - from the Devi Bhagvata Puran

Rambha and Karambha were two Danavas. Though they were born Danavas they were good at heart and did not cause any trouble. Karambha spent his days standing in the rivers, praying away. In a distance, Rambha spent his days under a Pipul tree meditating, praying to the fire gods. Seeing their meditation, Indra, the king of the Gods was scared. Afraid they wanted to take over his throne, Indra assumed the form of a crocodile, jumped into the river where Karambha was standing, devoured him.

 Hearing of the death of his brother, angry Rambha , heartbroken , decided to kill himself. Pleased with his meditation and seeing that he would kill himself, the Fire Gods appeared before him and stopped him, Further they asked Rambha to ask for boons. Rambha asked for a son who would cause destruction of Indra's pride.

Roaming around, Rambha was smitten by a she-buffalo he saw. A son was born from the union of the buffalo and the Danava. When Rambha was roaming with the she buffalo, he was attacked a male buffalo. A fight ensued and Rambha was killed. Seeing Rambha dead, Rambha's followers killed the buffalo  and cremated his body.

Shocked to see Rambha die, the she-buffalo also jumped into the funeral pyre. From the funeral pyre emerged two beings. Rambha was born as Raktabija and from the womb of the she buffalo emerged, the powerful Mahisha.