The Kurukshetra war · Mahabharata questions
Who killed Abhimanyu?
Abhimanyu was killed on the thirteenth day inside the chakravyuha by many warriors at once, against the rules of war. Drona, Karna, Kripa, Ashwatthama and Kritavarma broke his chariot, bow and armour, and the son of Dushasana killed the disarmed boy in a mace fight.
On the thirteenth day Drona forms the chakravyuha, a spiralling formation, on a day when Arjuna has been drawn to the far side of the field by the Samsaptaka warriors. Only Arjuna, Krishna, Pradyumna and the sixteen-year-old Abhimanyu know how to break into it. Abhimanyu knows the way in but not the way out. He says so, and Yudhishthira asks him to open the formation anyway, promising that the other Pandavas will follow him through the breach.
He breaks in. Jayadratha, holding the entrance with a boon from Shiva that he could hold off the Pandavas for one day, seals it behind him, and the boy is alone inside the whole Kaurava army. What follows is a deliberate violation of the code of war that the epic itself has been careful to set out. Six of the greatest warriors surround one: Drona, Karna, Kripa, Ashwatthama, Kritavarma and Brihadbala. On Drona advice Karna cuts Abhimanyu bowstring from behind. His chariot is smashed, his horses and charioteer killed, his sword and shield destroyed. He fights on with a chariot wheel, and finally the son of Dushasana meets him with a mace and strikes him down as he stands unarmed.
The consequences run through the rest of the war. Arjuna, returning to find his son dead, swears to kill Jayadratha before the next sunset or to enter fire himself, and the fourteenth day is fought to keep that oath. Bhima later kills Dushasana and his son. Abhimanyu widow Uttara is carrying the child who will become Parikshit and continue the Kuru line.
The epic treats the thirteenth day as the moment the war stops being a war fought by rules.