Role in the Kurukshetra war
When Hastinapura offers Drona the privilege of teaching the Kauravas, both Drona and Ashwatthama become loyal to Hastinapura and fight on the side of the Kauravas in the Kurukshetra war.
On the 14th day of the war, he kills a division of Rakshasas, including Anjanaparvan (the powerful son of Ghatotkacha), and defeates Ghatotkacha as well, breaking all his illusions but failing to kill the powerful demon. He also stands against Arjuna several times, trying to prevent him from reaching Jayadratha, but is unsuccessful. However, during the entire process of protecting Jayadratha, Ashwatthama, at one point in time, successfully saves Duryodhana's divine celestial armour and life by using his Sarvastra arrow and destroying the powerful Manavastra arrow launched by an angry Arjuna towards Duryodhana.
On the 10th day of the war, after Bhishma falls, Drona becomes the supreme commander of the armies. He promises Duryodhana that he will capture Yudhishthira, but he repeatedly fails to do so. Duryodhana taunts and insults him, which greatly angers Ashwatthama, causing a rift between Ashwatthama and Duryodhana. Krishna knew that it was not possible to defeat an armed Drona. So, Krishna suggests to Yudhishthira and the other Pandavas that if Drona was to be convinced that his son was killed on the battlefield, his grief would leave him vulnerable to attack.
Krishna hatches a plan for Bhima to kill an elephant named Ashwatthama while claiming to Drona that it was Drona's son who was killed. Ultimately, the gambit works (though the details of it vary depending on the version of the Mahabharata), and Dhrishtadyumna beheads the grieving sage.
After learning of the deceptive way his father was killed, Ashwatthama becomes filled with wrath and invokes the Narayanastra against the Pandavas.
When the weapon is invoked, violent winds begin to blow, the sound of thunder echoes, and an arrow appears for every Pandava soldier. Knowing that the astra ignores unarmed people, Krishna instructs all the troops to abandon their chariots and disarm. After getting their soldiers to disarm (including Bhima with some difficulty), the astra passes by harmlessly. When urged by Duryodhana to use the weapon again, desirous of victory, Ashwatthama says that if the weapon were to be used again, it would turn on its user.
In some versions of the story, like the Neelakantha Chaturdhara compilation, the Narayanastra destroys one Akshauhini of the Pandava arm. However, after the use of Narayanastra, a terrible war between both armies takes place. Seeing his Narayanastra fail to kill the Pandavas, Ashwatthama invokes the Agneyastra and launches it towards all the visible and invisible foes. The weapon soon overpowers and encompasses Arjuna with several fiery flaming arrows and creates havoc within the Pandava army. Upon witnessing this sight and realising the seriousness of the situation, Arjuna uses his Varunastra to subdue the effects of the Agneyastra, but by then it completely destroys another Akshauhini of the Pandava army, which only Arjuna and Krishna manage to survive. This shocks Ashwatthama as he leaves the battlefield confused and in doubt about his knowledge and skills. Later, Ashwatthama defeats Dhrishtadyumna in direct combat but fails to kill him as Satyaki and Bhima cover his retreat, in the process engaging in a battle against Ashwatthama. Ashwatthama defeats both the warriors and makes them retreat from the battlefield as well.[5]
By using an ordinary yet powerful bow, Ashwatthama fires millions of arrows at a time, which results in the stupefaction of Arjuna himself. Ashwatthama again overpowers Arjuna as he bathes in blood, but at last, Arjuna, left with no other option, pierces Ashwatthama's steeds, and the wounded steeds take Ashwatthama away from Arjuna. King Malayadhvaja of the Pandya Kingdom, one of the mightiest warriors of the Pandavas, fights against Ashwatthama. After a long duel of archery between them, Ashwatthama renders Malayadhvaja weaponless and gets an opportunity to kill him on the spot, but he spares him temporarily for more fighting. Malayadhvaja then proceeds against Ashwatthama on an elephant and throws a powerful lance, which destroys the latter's diadem. Ashwathama beheads Malaydhavaja, cuts his arms and also kills six followers of Malayadhvaja. Seeing this, all the great warriors of Kaurava army applaud Ashwatthama for his act.[6]
After the terrible death of Dushasana, Ashwatthama suggests Duryodhana make peace with the Pandavas, keeping in mind the welfare of Hastinapur. Later, after Duryodhana is struck down by Bhima and faces death, the last three survivors from the Kaurava side, Ashwatthama, Kripa, and Kritvarma, rush to his side. Ashwatthama swears to bring Duryodhana revenge, and Duryodhana appoints him as the commander-in-chief after Shalya was slain earlier during the day.
Along with Kripa and Kritavarma, Ashwatthama plans to attack the Pandavas camp at night. When Ashwatthama reaches there, he encounters Shiva in a terrifying ghost form guarding the Pandavas camp. Not recognising him, Ashwatthama fearlessly starts attacking the terrifying ghost with all his powerful weapons but fails to inflict even a single damage upon it, after which Ashwatthama starts meditating on Shiva while sitting inside a pit of fire, which finally impresses him, after which Shiva appears in his true form in front of Ashwatthama and offers him a divine sword. Then Shiva himself enters the body of Ashwatthama, making him completely unstoppable.
After Ashwatthama enters the camp, he first kicks and awakens Dhrishtadyumna, the commander of the Pandava army and the killer of his father.[7] Ashwatthama beats up and strangles the half-awake Dhrishtadyumna as the prince begs to be allowed to die with a sword in his hand, ultimately choking him to death. Ashwatthama proceeds with butchering the remaining warriors, including Shikhandi, Uttamaujas, Yudhamanyu and many other prominent warriors of the Pandava army. Even though many warriors try and fight back, Ashwatthama remains unharmed due to his activated abilities as one of the eleven Rudras. Those who try to flee from Ashwatthama's wrath are hacked down by Kripa and Kritavarma at the camp's entrances.
After the slaughter, the three warriors go to find Duryodhana. After relaying to him the deaths of all the Panchalas, they announce that the Pandavas have no sons with whom to rejoice in their victory. Duryodhana feels greatly satisfied and avenged at Ashwatthama's ability to do for him what Bhishma, Drona, and Karna could not. With this, Duryodhana breathes his last, and the next morning, the three remaining members of the Kaurava army perform the cremations of the dead.
The Pandavas and Krishna, who were away during the night, now return to their camp. Hearing the news of these events, Yudhishthira faints, and the Pandavas become inconsolable. Bhima angrily rushes to kill Drona's son. They find him at Sage Vyasa's ashram near the bank of the Ganges.
The now-triggered Ashwatthama invokes the Brahmastra against the Pandavas from a tiny blade of grass to fulfill the oath of killing them. Krishna tells Arjuna to fire his own Brahmastra as an anti-weapon against Ashwatthama to defend themselves. Vyasa intervenes and prevents the destructive weapons from clashing against each other. He asks both Arjuna and Ashwatthama to take their weapons back. Arjuna, knowing how to do so, takes it back.
Ashwatthama, however, not knowing how, redirects the Brahmastra towards the womb of the pregnant Uttara in an attempt to end the lineage of the Pandavas.
Krishna saves Uttara's unborn child from the effects of the Brahmastra, on the request of Draupadi, Subhadra, and Sudeshna. Ashwatthama was then made to surrender the gem on his forehead and cursed by Krishna that he would roam in the forests until the end of the Kali Yuga with blood and puss oozing out of his injuries and cry for death, but death would not meet him.[8]
