Amba was the eldest daughter of the king of Kasi. She had two younger daughters by the name Ambika and Ambalika. The raja of Kasi arranged for the swayamvara of his three daughters and he had invited all the princes and kings except Hastinapur. In Hastinapur, Bhishma, the great knight, was guardian of the imperial house of the Kurus and he had made a vow in his youth that he would never marry. Although he was the successor of the throne of Hastinapur, he made that vow in order to enable his father to marry a certain fisher-maid, Satyavati by name, on whom he had set his heart. When Bhishma`s father, Santanu, was dead, Bhishma set on the throne his own half-brother, Vichitravirya. Thus, it was necessary that he should find a suitable marriage for this brother in order that the royal succession might be duly secured. When Bhishma heard of the bridal tournament at Kasi, he decided that the opportunity was an excellent one to secure suitable queens for the young Vichitravirya, and he determined to seize the three maidens and do combat for them against all comers.

Swayamvara of the daughters of the raja of Kasi
The raja of Kasi invited all the kings and princes in the earth, but he did not send any invitation to Hastinapur. When Bhishma came to know about the swayamvara, he thought it to be a suitable opportunity to get queens for his brother Vichitravirya. In accordance with that purpose, Bhishma set out for Kasi as a simple gentleman without a retinue. He arrived at the royal lists, and saw the three maidens, all unrivalled for beauty and richly robed and ornamented, and before them, ranged on thrones and in cars, under royal umbrellas and pearl-embroidered canopies, each with his proper cognizance blazoned on his banner, all the greatest princes and kings of the earth. Bhishma paused for a moment to survey the scene and then with a voice that was like the roaring of a lion, he sounded three times the great battle-cry that was to summon his rivals to mortal combat.

Bhishma seizes Amba, Ambika and Ambalika
Bhishma, son of Santanu, seized the three maidens of Kasi and declared that he had seized them by force and challenge anyone from among several warriors who were present there to stop him. No one dared to accept the challenge, and in the twinkling of an eye the battle-chariot of Bhishma turned away and swiftly drove down upon that part of the lists where the three princesses waited surrounded by their ladies. They were placed by their attendants on the chariot of Bhishma, and even while the great counter-challenge was ringing out on all sides, and angry kings had risen, with swords unsheathed, to leap to chariot or elephant or horseback, Bhishma stood alert and smiling, with bow drawn and his back to the royal maidens, ready to do battle for his prize against a world in arms. He defeated all the kings and princes and with a shower of arrows he stopped the rush of enemies that came upon him from all sides at once. At last, all the kings of the earth broke ranks and accepted their defeat. And Bhishma, having vanquished several sovereigns, retained his royal prize of three princesses, and escorted them back to Hastinapur, the royal city, to the queen-mother Satyavati.

As the wedding-day of Vichitravirya drew near, Amba told to Bhishma about her prior betrothal to the king of the Shalwas. Then Bhishma, with the consent of Satyavati, send Amba to the capital of the king of the Shalwas escorted carefully by a number of old Brahmins and her own waiting-woman, who had from childhood been her nurse.

Amba Was Rejected by King of Shalwa
Amba reached the court of the Shalwas and told everything that befell her and told the king to accept her as his queen. But some blindness and perversity had come upon the king of the Shalwas and with lightness and laughter, he declared that he did not want a wife who had once been carried off by Bhishma and intended for another`s bride. Then he taunted the princess with having gone to Hastinapur cheerfully. But Amba could truthfully urge that she had wept all the way. Finally, the king of Shalwa showed himself simply indifferent, and though she made her feeling clear over and over again with sincerity that all her life after it made her hot to remember, he showed not the slightest affection for her, but turned away from her, casting her off as a snake discards his old skin. When the maiden at last understood that this was the king`s intention, her heart was filled with anger and she turned, crying softly, and haughtily and went forth from the city.

Suffering the deepest humiliation and scarcely knowing where to turn, the royal maiden for that night took refuge in one of the great forest-hermitages of the time, known as ashramas, of which her own grandfather happened to be the head. Her heart was full of pain and her whole mind was in confusion. She was in confusion to blame the king of Shalwa or Bhishma or herself or her father for her misfortune. She once cursed her father for announcing that prowess should be the dower of his daughters and then she would blame Bhishma. If Bhishma had not captured her, if he had not taken her to Hastinapur and if he had not arranged for her expedition to the king of the Shalwas, that trouble would not have come upon her. She thus blamed herself, her father, and Bhishma all by turns, but she never blamed the king of Shalwas for his lightness and vanity.

Parasurama Fights with Bhishma
After being rejected by the king of Shalwas, Amba stayed in the hermitage and gradually, as she grew calm and took the help and advice of the old sages of the ashrama, her mind began to settle on Bhishma as the source and root of her woes, and the destruction of Bhishma gradually became the motive to which all her self-severities were to be directed. There took a great mythical combat against Bhishma on Amba`s behalf by Parasurama, incarnation of Vishnu, who had been his early teacher. The combat lasted for many days, being fought with all the splendour and power of warring divinities, till at last it was brought to an end by the intervention of the gods, surrounded by all the celestial hosts. Since the gods feared to see the exhaustion of mighty beings that owed each other reverence and affection and could by no means kill one another. But when Amba was called into the presence of Parasurama to hear the news of the cessation of the conflict, she merely bowed and thanked the old warrior with great sweetness for his energy on her behalf.

Amba`s Penance and Her Boon from Shiva
When Parasurama was not able to defeat Bhishma and the war between them was stopped by the gods, Amba thanked Parasurama for the waste of his energy on her behalf and vowed to find the means herself in order to slay Bhishma. Parasurama smiled at the resolve of a maiden to kill a knight like Bhishma and then Amba rose up and with her head high and despair on her face. She was sure that there was no one to help her except her own self. From that time she behaved extraordinary. Month after month she went on fast and underwent penances. Her hair became matted and she grew thinner and thinner. She would stand still for hours and even for days in silence. At last Lord Shiva, the Great God, appeared before her, and standing over her with the trident in his hand, he asked to grant her a boon. Amba replied that she would only require the defeat of Bhishma and Shiva granted her the boon by saying that she would be responsible for the death of Bhishma. Shiva told her that she would take a new birth and afterwards would obtain manhood and become a fierce warrior and she would also remember the whole of her present life. Then Amba prepared a funeral pyre and sacrificed her body in the flames in order to reborn.

Amba Reborn as Shikhandi
Amba was reborn as the daughter of Drupada, the king of Panchala, who had worshipped Shiva and was also blessed by the lord that his queen would beget a daughter but in due course the child would attain manhood. Thus, Amba was born and was named Shikhandi. Later, Shikhandi was blessed by Yaksha in a jungle and attained manhood for the rest of his life. As blessed by Lord Shiva, Shikhandi remembered everything of his previous life as Amba and the resolve to kill Bhishma in a battle. The desire of Shikhandi was fulfilled when in the great battle at Kurukshetra Shikhandi was accompanied by Arjuna and was responsible for giving mortal wounds to the Kuru commander.

The life of Amba, the eldest daughter of the king of Kasi, was spent in severe penance and austerities, and her goal remained only to defeat Bhishma. She was blessed by Shiva and was reborn as Shikhandi to the eldest queen of king Drupada. As per the boon of the Lord she attained manhood and became a brave and courageous fighter, being well-acquainted with the use of all the weapons. In the battle at Kurukshetra, which was fought between the Pandavas and the Kauravas, Shikhandi was responsible for laying Bhishma flat on a bed of arrows in the battlefield.