I have answere this qn before. but here inbetween lines what dharma karna followed. he did not follow any dharma. that is why it failed to protect him. now pl. read what i have written earlier to assess his character.This karna of mahabharatha was given more than life image by poets for rason i fail to understand. perhaps maybe all of them felt sorry for fate always went against him. but are we not the makers of our own destiny . let me substantaite my answer.
karna's previos birth: he was an asura (some say he was a king with aasuric bent of mind) and disturbed the penance of rishis. he was killed by sage Nara who was again born as arjuna
birth: he was born out of wedlock to kunti who tried to test the efficacy of a mantra given by the Durvaso maha muni who she served as a guru. without sraddha ( i.e complete faith on the guru, his teachings or his upadesa) the fruits of your actions will not bear good rsults. compare the same kunti who used the same mantra with the permission of h
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Karna was a born warrior but a total failure as a person.
He was bogged down by his unpleasant personal identity. Great men of his stature is expected to rise above such shortcoming, which he never could. Instead, in order to salvage some pride he joined the evil company of Duryodhana &Co and became a mute witness of their misdeeds. His charity is faulty, if not false. Endangering ones life knowingly, which is in no way for the good of humanity, is NOT charity. It is suicidal. Karna was simply giving up his life, torn apart by the peculiar life circumstance he fell into ! He failed in his darma, both as a warrior and as a person !