When Duryodhana revealed the treachery, Shalya is astounded but is compelled to grant a boon due to the hospitality. Unable to turn down Duryodhana's request to join the Kauravas, Shalya met the Pandavas and apologised for his mistake. Nakula and Sahadeva grew enraged, saying that Shalya had truly proven that Nakula and Sahadeva were not real brothers to the Pandavas, but only step-brothers. Yudhishthira quickly stepped in and reprimanded the twins, commanding that they were never to again cheapen their relationship by saying they were "step" brothers. At this point, Shalya realised that he had underestimated their brotherly bond. Yudhishthira promised to Shalya that he would kill him during the eve of the war. Yudhisthira's plan against Karna Prior to the start of the war, Yudhishthira met with his elders on the Kaurava side, seeking their blessings. Shalya readily offered his blessings to Yudhishthira, wishing him victory. Yudhisthira feared that Karna could single-handedly kill the Pandavas. In order to dissuade him from combat, Shalya was requested by Yudhishthira to heap praises on his brothers in order to infuriate Karna, to distract him on the field of battle. 1st-13th days Though not spirited in his fight, Shalya confronted many great warriors during the war. On the first day, he attacks Yudishthira and snaps his bow. However, Yudishthira takes another bow and wounds Shalya. Shalya killed Uttara Kumara on the first day of the war. He killed the boy with his spear after a fantastic duel, and subsequently hailed his brave death. On the second day, his eldest son Madranjaya is killed by Virata as revenge for Uttara. 13th-17th days On the 13th day, Shalya's sons Rukmangada and Rukmaratha were killed by Abhimanyu; Shalya himself is helpless against Abhimanyu's attacks. On the 14th day, he tries to stop Arjuna’s advance towards Jayadratha but is defeated; injured so badly that he cannot even sit down. During the night battle at the end of the day, he vanquishes Virata and makes him flee. Karna's charioteer On 16th day of battle, Karna defeated, but spared the lives of Nakula and Sahadeva, stating that they are younger and not his equals, therefore not deserving of death by his hands. He proceeded to clash with Arjuna, having previously promised Kunti that he would not attempt to slay any Pandava except Arjuna. During the course of the battle, Karna invoked the Ashwasena snake on his arrow and directed