The Kurukshetra war · Mahabharata questions
How did Karna die?
Karna was killed by Arjuna on the seventeenth day. His chariot wheel sank into the ground, as a brahmin curse had promised, and he forgot the mantra for his greatest weapon, as Parashurama had cursed him to. Stepping down to free the wheel unarmed, he was shot with the anjalika arrow.
Karna death is arranged by the epic long before it happens, through a series of losses that strip away every advantage he was born with.
He is born with natural armour and earrings that make him invulnerable; Indra, as a brahmin beggar, asks for them on behalf of Arjuna and Karna cuts them from his body and gives them away, taking in exchange a single-use spear. He learns the brahmastra from Parashurama by claiming to be a brahmin, and when the deception is discovered Parashurama curses him to forget the mantra when he needs it most. He accidentally kills a brahmin cow and is cursed that his chariot wheel will sink into the earth at the moment of his greatest danger. He gives Kunti his word that he will not kill any of her sons except Arjuna. He spends his one spear on Ghatotkacha on the fourteenth night, because that weapon was the only thing that could stop the rakshasa, which is exactly what Krishna intended.
On the seventeenth day he faces Arjuna as commander of the army, with Shalya as his reluctant charioteer. All the curses come due at once. The wheel sinks. The mantra will not come. He asks Arjuna to honour the rule that a warrior on the ground and disarmed must not be struck, and Krishna answers by listing the rules that were broken against Abhimanyu and against Draupadi in the hall. Arjuna shoots, and the anjalika arrow takes Karna head.
Only afterwards, at the funeral rites, do the Pandavas learn from Kunti that Karna was her first son, born before her marriage, and their eldest brother. Yudhishthira reaction is a curse on all women, that they will never again be able to keep a secret.