Once again Duryodhana was with Drona complaining that he was not doing enough to defeat the Pandavas as still he had some soft corner for them in his heart. Drona once again repeated his old arguments, but this did not satisfy Duryodhana. Drona was in introspective mood. This entire life came before him in his mind. His transformation from an ascetic of a great lineage and achievements to him animosity, with Drupada and then his taking up the job of the teacher of the Kuru princes. Then he remembered his days in the court. He had become attached to the worldly things. He could not oppose the wrongs done by Duryodhana. Now he was reduced to such a state that he had to listen to the harsh words of Duryodhana.
Duryodhana sharp words had cut Drona to quick. He had already given up the righteous policy of Bhishma of fighting during the day only. Now fighting was done during the night also. Drona used Brahmastra against the common soldiers,which was against the all canons of laws of righteous fight. Divine astras could be used against one’s equals only. Dhristadhyumna came to fight with Drona again. Drona had killed two great warriors of the Pandavas sides. Drona killed three sons of Dhristadhyumna and Drupada and Virata. Dhristadhyumna was now wild at the killing of his sons and of his father. He attacked acharya again and again but did not succeed. Drona too used many astras against him and finally he invoked Brahmastra. Dhristadhyumna could save his life by contering it with another Brahmastra. By using Brahmastra Drona had killed twenty thousand of common soldiers. Dhristadhyumna took an oath to kill Drona on that day.
Krishna told Yudhisthira that Drona would finish his entire army if not checked. The only way to check Drona was to make him lay down his arms. That was possible only Drona was told that his son had died. Reluctantly Yudhisthira agreed.
Bhima killed an elephant named 'Ashvatthama'. Then he loudly announced for all to hear, 'Ashvatthama' is killed. Ashvatthama is dead. Drona was stunned with grief. Asvatthama could not have been killed by anyone. He had the blessings of lord Shiva. Not able to believe Bhima, Drona turned to Yudhisthira and asked if that was true. Yudhisthira said, Ashvatthama is killed " Elephant not the Man " he added in a low voice and the last part of the sentence was lost in the loud blowing of the conch of Krishna, Panchajanya. It is said that Yudhisthira’s chariot always, moved four inches above the ground. So strong was his commitment to dharma. He had never spoken a false word till that time. After this act, his chariot came down to earth and he became like any other mortal.
Now, Drona was so full of grief that he put down his arms and with a sword, Dhristadhymna cut off his head. The old prophecy that he would be the cause of Drona’s death came true. The oath of Dhristadhyumna was fulfilled. The gloom descended on the Kauravas camp hearing this news but there was no celebration in the camp of the Pandavas. Thus the fifteenth day had proved to be the most cruel day of the war. Drona’s divine astras and Brahmastra had taken a toll of twenty-four thousand Kshatriyas. The army of Kauravas was retreating in panic. The Kauravas king and the warriors were huddled together in consultation, Ashvatthama was beyond control to hear his father’s cruel death. He was taking dreadful oaths of sending all the Pandavas to their death. Arrival of Ashvatthama put some courage in the Kauravas army, Led by Ashvatthama, the Kaurava army once again prepared itself for fight.
The Pandavas were taken by surprise by the sounds of drums and trumpets by Kauravas army. They were jerked out of their complacent by the lusty blowing of conches by Kaurava warriors. Arjuna said, It is Ashvatthama who is leading the army. He is like a wounded snake.