Mahishasura had a power that made him the strongest male in the world, his name meaning Buffalo-demon. He had a boon that he could not be defeated by any man. When he ravaged the Three Realms of the universe, none could withstand his virulent ferocity. His brutal strength and impregnably hard muscles made it impossible for any warrior or weapon to stop him. He declared himself the master of the universe and started his atrocious rule.
The humiliated gods retreated to a hidden haven, and their frustration slowly turned to anger. Out of their combined will, they created the goddess Durga, the champion they hoped would bring them salvation. Durga was evoked as a female form of utmost beauty, strength and sensuality. She was the most powerful form ever, and the gods sung her praise and begged her to save them.
She set out to battle Mahishasura alone, along with her ride, a great lion. Mahishasura, when informed of a lone woman coming to challenge him, casually ordered his generals to look into the matter. But the scenario changed when he got the news that his entire army had been massacred by Durga easily. He went forth to face her himself.
When Mahishasura faced the goddess, he was staggered by her beauty and attractive appeal. He was overcome by lust and expressed his desire to marry her. But Durga rejected his proposal with disdain and challenged him to battle. At this, Mahishasura decided to take her by force and attacked her.
Durga was a champion in all forms of armed combat (the reason why she is symbolically depicted as a multi-limbed figure in popular images), and had overcome the army easily. But with Mahishasura, it was evenly matched. Her lithe grace and dazzling skill was countered by the demon's bestial ferocity and monstrous strength. Moreover, her strikes with the weapons of the gods went futile against the demon's iron hard sinews.
After a long period of stalemate, the combatants forsook their weapons and met each other bare handed. With any other person, a bout of wrestling with Mahishasura would be a vicious path to destruction. But with Durga, it was another matter. She was the strongest form ever, the essence of all strength. She met the demon with a dance of amazing grace and sensuality, simultaneously resisting his advances towards her. Mahishasura was seized with a craze that was both bloodlust and desire, and he dashed at the seductive form before his eyes madly. Durga grabbed him like he was a toy, and threw him to the ground. Mahishasura tried to rise, but the goddess came forth and placed her left foot on his chest, pressing him down hard. She began to crush him underfoot. Mahishasura struggled in vain to free himself as he felt his body give way under the tremendous power, and he realised he was outmatched by the woman towering over him. He begged for his life and pleaded, - but Durga poured on more pressure as he thrashed about wildly, crushing the 'unbreakable' chest of the demon king and killing him, agonized screams and thick blood streaming from his agape mouth.
Durga stood over the vanquished body in victorious glory, with one foot upon the demon's broken chest and another on her lion, and the gods were saved from their peril.
Before Durga took her leave from the gods, she promised to return and help them if the need ever arose again.