In Hindu scriptures, Mahishasura was an asura, a race of divine spirit beings who are the opponents of the Deva. Mahishasura's father Rambha was king of the asuras. He once fell in love with Princess Mahishi, who was cursed to be a water buffalo. Mahishasura was born out of this union. Because of this, he is able to change between human form and buffalo form at will. The name Mahishasura comes from the Sanskrit word for buffalo, Mahisha.
This painting shows a pivotal battle between Durga and a powerful demon named Mahasura. The demon, with an animal head and purple skin, appears three times, attacking the goddess with bow and arrow, sword and shield, and trident (this weapon is shown snapped in two, a sign that he will eventually lose).
The two demon brothers Rambh and Karambh arrived on the throne of the Underworld. Their Mother, Danu, instructed them to do penance and obtain desired boons. Hence, Rambh and Karambh did penance to please Agni and Varun (Fire/Water) respectively. Rambh began to do penance in Agni chakra, whereas Karambh was half immersed in river water while doing penance. Lord Indra took disguise of a crocodile and killed Karambh, while Rambh successfully completed his penance. Rambh received a boon from Agni. This boon would allow him to obtain an extremely powerful son who would rule over the three worlds in this universe. Rambh fell in love with Mahishi (buffalo woman) and they married. Mahishi soon became pregnant. When her lover, a Mahish, tried to abduct her Rambh came in to protect his wife. Rambh was killed by the Mahish. In the cremation process of Rambh, Mahishi jumped into the fire to sacrifice her life to express her love for her husband. Yama was stopped from taking away the soul of Rambh. Hence, Rambh got retained into the womb of Mahishi.
From the cremation fire emerged two demons namely Raktabeej (rebirth of Rambh) and Mahishasur (the child of Rambh). The demon Mahishasur obtained a boon from Lord Brahma which indicated that no man would kill him. He gathered strong powers from Lord Brahma as a reward for his penance.
Mahishasur also gathered a large demon army to win for the heavens. In Heaven, Indra learned about the boon that Mahishasur got from Lord Brahma. He sent in a large heavenly army. Mahishasur came to the battlefield with his army as well with Indra's. The demons were chanting for Mahishasur while the heavenly army was chanting for Indra. Indra warned Mahishasur to go back where he belonged, but Mahishasur refused. A severe battle began. The heavenly army failed to kill Mahishasur's army. Mahishasur's army was so powerful and strong, and Mahishasur defeated Indra by obtaining the heavens. All Gods went to Shiva, Brahma and Vishnu to destroy Mahishasur. Shiva, Brahma and Vishnu assembled forth together and from their anger emerged rays of light which were combined onto other flames with other Gods who had lost their anger. The rays of light were combined onto other flames, and they issued forward together taking the shape of a woman. The woman, who was wearing an old dress, had a fair complexion, long black hair, and uncountable hands. All of the Gods presented her with new red clothes, jewelry, a crown, a tiger for her vehicle, weapons, makeup and many other items. The woman put on makeup to make herself look pretty. Shiva gave her a trident, Vishnu gave her a discus, Brahma gave her a water pot and rosary, Marut gave her a bow and arrow, Indra gave her a thunderbolt, Wind God gave her a conch shell, Fire God gave her a spear, Rain God gave her a conch shell, Sun God gave her his powers of the bright 10,000 suns inside her most powerful body, Rudra and Veerbhadra both gave her a shield, sword and scimitar, Lord Yama gave her a lasso, Vishwakarma and Kuber gave her a battle-axe, lotus, weapon made out of thorns, spear, longsword, vajra, spade, baton, beating stick, cleaver, javelin, snake, and Wind God gave her a noose. The Gods kindly asked her to destroy the evil demon Mahishasur. Upon hearing Lord Vishnu giving her the name of Goddess Durga, she spoke out to the Gods announcing that she would annihilate the evils in many forms. She caused trouble for the demons by making the three worlds shake, including the heavens and hell. That shake echoed throughout the skies, and the seas trembled as the Goddess descended on earth. The Gods and sages beheld the Supreme Goddess. The demon King was terrified and ordered his enormous army to attack the one who makes the storming sound. Goddess Durga on her tiger saw the uncountable army of demons. Ugrasen came with sixty thousand chariots, Chixsur came with one million horsemen, Vidhan came with one hundred soldiers and Vashkaal came with countless demons. Demons of Mahishasur saw Durga, heard the roar of her voice, and the twang of her bow string echoed throughout the heavens to hell. The feet sank to the netherworld, the crown kissed the skies and the thousand of hands filled with weapons filled the sky in all directions. The furious war began with Durga and the demons attacking each other with opposite weapons. All bad weapons each demon warrior uses, all of the opposite weapons of Durga strikes the demon weapon and then breaks, this went on for quite some time. The demons then attacked her with a rain of arrows. About one hundred arrows flew up in the sky. Durga used the same number of arrows and the demon arrows were broken by Durga's opposite arrows. Again, this went on for quite some time. Durga used almost all of her weapons including the trident, mace, discus, arrow, shield, sword, scimitar, battle-axe, weapons made out of thorns, spear, longsword, vajra, spade, baton, beating stick, cleaver, thunderbolt and javelin. These weapons stabbed the demons; The demons were beheaded, bruised and beaten with a beating stick. The demons fought the Goddess with their finest weapons like javelins, daggers, scythes, spears, pestles, swords and battle-axes but all of the demon weapons were smashed to pieces. They flung nooses at the Goddess. The tiger of Durga himself, with his paws and claws, managed to trample half of the unhurt demons by striking them with his paws, scratching them with his claws, ripping off their heads, arms, and legs, choking them, stabbing their chests, drinking their blood, breaking their bones and necks, twisting their hands and legs, and swinging them away. Durga saw that her tiger was a great demon-fighting warrior and congratulated him. But there were still the army of one hundred demon soldiers and countless demons. Durga created the same number of male warriors and female warriors. The warriors of Durga managed to fight the rest of the endless demon army of Ugrasen, Vashkaal, Chixsur and Vidhan. As a celebration for the victory of Durga's army, they started dancing, singing, playing the drums, flutes, sitars, and many more instruments. Durga pinned down demons with her weapons and killed them by ringing her strong, mighty bell or dragging them with her noose. Many were beheaded by the Goddess and smashed by her mighty mace. Some were crushed by pestle and their chests were torn by the Goddess's trident. Others were pierced by the Goddess's arrows. Decapitated demons rose yelling to the music played by the Goddess's soldiers, and fought the Goddess Durga with their finest weapons. As fire reduced twigs and leaves into ashes, likewise Durga destroyed the imperial army of Mahishasur with the help of her tiger within minutes. All Gods, saints, sages, celestial beings, Yakshs, Yakshinis, men, women, and children paid gratitude to Goddess Durga for the killing of Mahishasur's demon army. The remaining 17 demon men of Mahishasur, Chixsur, Chamar, Ugrasen, Utpal, Vidal, Vidhan, Ugravirya, Tamra, Trinetra, Udagrasur, Karalasur, Vashkaal, Durdhara, Mahahanu, Ugrasya, Baskalasur, Udyatarasur, Virlaxa and Durmukh were all generals. Durga killed altogether the 17 generals with her weapons. For her counterattacks, she dispatched the four-fold demon infantries with her tiger and other demons. She sucked out the remaining life of the demons by blowing them in one strike. She rained arrows at Udagra, Asilom, Parivarita, Virhalax and Vaskalasur as the drivers of the endless number of chariots. Now, Mahishasur was the last demon to enter the battlefield. He fought Durga with his different weapons. Once again he uses the bad weapons, and Durga uses the opposite weapons.They strike each other and break. This lasted for quite some time. The demon then attacked her with a rain of arrows. About one hundred arrows flew up in the sky. Durga used the same number of arrows and then, the demon arrows were broke by Durga's opposite arrows. After that, He kept changing into many different forms, such as a lion, warrior, buffalo, and elephant. Goddess Durga killed his different forms by using a scimitar and sword. Later, Mahishasur again obtained the form of a buffalo and attacked Durga with trees, rocks, boulders, and mountains, but Durga had managed to destroy them all. At last, the Goddess drank water from her cup and announced to Mahishasur that she would kill him. This time, Durga trampled the buffalo with her tiger. Mahishasur ame out of the buffalo's mouth, trying to kill the Goddess with his sword. Durga stabbed his body with her trident. All Gods, saints, sages, celestial beings, Yakshs, Yakshinis, men, women and children paid gratitude and started to do a prayer ritual to her.
In Kerala, there is a story about Mahishasur's sister, Mahishi, who was adopted by his Uncle. She had the head of a female buffalo. After the death of Mahishasura, Mahishi-the asura princess took the throne and continued the war against gods. She had obtained a boon from Lord Brahma that only the son of Shiva and Vishnu could kill her. The main aim of her life was to destroy Goddess Parvati, who's incarnation Kathyayani, also known as Durga, had killed her brother.