After the fall of Bhisma, Doryodhana wanted Karna to be the next commander-in-chief. He knew that Karna was capable of defeating Arjuna and asked him to take  charge of the army. However Karna asked Duryodhana to make Drona the commander-in-chief as this would be acceptable to everyone. Duryodhana liked the idea and Dronacharya was made the commander-in-chief. The Kaurava army got a new breath of life because they were sure that the brave guru would lead them to victory. Karna had pledged that he would not fight under Drona, so he left the battlefield. But Drona requested him to forget all grudges and joined the battle for the sake of his friend, Duryodhana. To everybody's joy, Karna agreed and joined the battle.  Duryodhana knew that Drona would never kill any of the Pandavas so he asked him to capture Yudhisthira alive. Drona did not mind carrying out this order and rearranged the army to achieve this end.