Who killed Dronacharya?

In the epic Mahabharata, Dronacharya, the royal teacher and great warrior, was killed on the fifteenth day of the Kurukshetra war. He was not directly slain by any one warrior but rather through a tactical deception planned by the Pandavas and executed by Dhrishtadyumna, the commander of their army.

The strategy was led by Krishna, who advised that Drona could only be defeated if he lost his will to fight. Since Drona was invincible while holding his weapons, Bhima loudly declared that “Ashwatthama is dead,” referring to an elephant named Ashwatthama. Hearing this, Drona asked Yudhishthira, who, bound by truth, replied ambiguously “Ashwatthama is dead… the elephant.”

Believing his beloved son was killed, Drona fell into deep sorrow and laid down his weapons. Taking advantage of this moment, Dhrishtadyumna — born to kill Drona — approached and beheaded him. Thus, though Yudhishthira’s half-truth and Krishna’s strategy caused his downfall, Dhrishtadyumna was the one who actually killed Dronacharya on the battlefield.