Karna meets Duryodhana for the first time in Hastinapura during archery lessons from Drona, an event described in section 3.293 of the Mahabharata.
They become close friends not long after, when Karna and Arjuna are at a weapons trial competition.
Duryodhana sees in Karna a man who is an equal of Arjuna in martial abilities, and someone to befriend to balance out Arjuna and thereby "diminish the Pandavas".

Before the competition starts, the contestants must announce their lineage so that men of equal ranks are placed together.
After Arjuna announces his royal lineage, it is time for Karna to present his lineage.
If Karna were to announce his charioteer lineage, it would disqualify him from competing against Arjuna.
Duryodhana steps in and says Karna is an Arajna (a non-king, but also a word play on Arjuna) but announces that he is offering to anoint Karna as the king of Angas (Bengal).
Once Karna is a king, states Duryodhana, Arjuna would not have the excuse to avoid Karna and not compete with the able warrior.
Karna accepts the anointment, becomes a king that day.
It also transforms him into a loyal friend to Duryodhana, with an eagerness to reciprocate the favor.
Karna asks Duryodhana what he would want in return for the kingdom he just gave out of his empire, Duryodhana replies, "I want your endless friendship Karna".

For the consecration ceremony, Karna's father arrives.
Bhima, one of the Pandavas, ridicules him for his low status and calls him dog-like.
The public insult of his father makes Karna hate the Pandavas.
At the end of the competition, while everyone rejects Karna, Duryodhana expresses amity to Karna by "taking Karna by his hand".
Karna feels Duryodhana is that friend who stood by him when everyone rejected him.
Duryodhana becomes Karna's lifelong close friend.
In Karna, Duryodhana finds an able man and talented commander who can help him gain and retain power over an empire.
In Duryodhana, Karna finds a caring friend and resourceful supporter when almost everyone is bent on ridiculing and disowning him.

Karna evolves into a character who shares Duryodhana's view that Pandavas are bad and enemies, though for different reasons.
Karna participates with Duryodhana in schemes to effect the downfall of the Pandavas.
Duryodhana provides the goals, Karna conspires the means to get there.

In the final year of the exile of the Pandavas, Duryodhana plans to sow dissension and keep the entire empire to himself.
In contrast, Bhisma and Drona suggest a conciliation and dividing the kingdom into two, half for Kauravas and other for Pandavas.
Karna, in contrast, adopts the hawkish approach and becomes the first to suggest a direct confrontation in the form of the Kurukshetra war.
He calls for "together we should slay the Pandavas" as the final solution.
Karna persistently recommends violence and an all-out war, to settle things once and for all, by good brave warriors.
Karna also accuses Bhisma and Drona as covetous materialists and dishonest in counseling Duryodhana with non-violent strategies.
Duryodhana has evil intentions and is a bad king, but it is Karna who fuels Duryodhana's ambitions and fights his battles.

With Duryodhana, Karna is a key participant in insulting the Pandavas and Draupadi.
He humiliates the Pandavas with his gift of speech and mocks Draupadi, then calls her a "whore" and asks Duhshasana to strip her off her clothes.
It is Karna's language and insults that hurt the Pandavas and Draupadi the most, a sentiment that is noted in numerous verses of the Mahabharata such as 3.13.113 and 5.93.11.
Yet, states the Mahabharata scholar Alf Hiltebeitel, "remarkably, Karna regrets his harsh words to Draupadi and Pandavas", in verse 5.139.45, where he confesses he spoke so to please Duryodhana.
Karna meets Duryodhana for the first time in Hastinapura during archery lessons from Drona, an event described in section 3.293 of the Mahabharata. They become close friends not long after, when Karna and Arjuna are at a weapons trial competition. Duryodhana sees in Karna a man who is an equal of Arjuna in martial abilities, and someone to befriend to balance out Arjuna and thereby "diminish the Pandavas".
Before the competition starts, the contestants must announce their lineage so that men of equal ranks are placed together. After Arjuna announces his royal lineage, it is time for Karna to present his lineage. If Karna were to announce his charioteer lineage, it would disqualify him from competing against Arjuna. Duryodhana steps in and says Karna is an Arajna (a non-king, but also a word play on Arjuna) but announces that he is offering to anoint Karna as the king of Angas (Bengal). Once Karna is a king, states Duryodhana, Arjuna would not have the excuse to avoid Karna and not compete with the able warrior. Karna accepts the anointment, becomes a king that day. It also transforms him into a loyal friend to Duryodhana, with an eagerness to reciprocate the favor. Karna asks Duryodhana what he would want in return for the kingdom he just gave out of his empire, Duryodhana replies, "I want your endless friendship Karna".
For the consecration ceremony, Karna's father arrives. Bhima, one of the Pandavas, ridicules him for his low status and calls him dog-like. The public insult of his father makes Karna hate the Pandavas. At the end of the competition, while everyone rejects Karna, Duryodhana expresses amity to Karna by "taking Karna by his hand". Karna feels Duryodhana is that friend who stood by him when everyone rejected him. Duryodhana becomes Karna's lifelong close friend. In Karna, Duryodhana finds an able man and talented commander who can help him gain and retain power over an empire. In Duryodhana, Karna finds a caring friend and resourceful supporter when almost everyone is bent on ridiculing and disowning him.
Karna evolves into a character who shares Duryodhana's view that Pandavas are bad and enemies, though for different reasons. Karna participates with Duryodhana in schemes to effect the downfall of the Pandavas. Duryodhana provides the goals, Karna conspires the means to get there.
In the final year of the exile of the Pandavas, Duryodhana plans to sow dissension and keep the entire empire to himself. In contrast, Bhisma and Drona suggest a conciliation and dividing the kingdom into two, half for Kauravas and other for Pandavas. Karna, in contrast, adopts the hawkish approach and becomes the first to suggest a direct confrontation in the form of the Kurukshetra war. He calls for "together we should slay the Pandavas" as the final solution. Karna persistently recommends violence and an all-out war, to settle things once and for all, by good brave warriors. Karna also accuses Bhisma and Drona as covetous materialists and dishonest in counseling Duryodhana with non-violent strategies. Duryodhana has evil intentions and is a bad king, but it is Karna who fuels Duryodhana's ambitions and fights his battles.
With Duryodhana, Karna is a key participant in insulting the Pandavas and Draupadi. He humiliates the Pandavas with his gift of speech and mocks Draupadi, then calls her a "whore" and asks Duhshasana to strip her off her clothes. It is Karna's language and insults that hurt the Pandavas and Draupadi the most, a sentiment that is noted in numerous verses of the Mahabharata such as 3.13.113 and 5.93.11. Yet, states the Mahabharata scholar Alf Hiltebeitel, "remarkably, Karna regrets his harsh words to Draupadi and Pandavas", in verse 5.139.45, where he confesses he spoke so to please Duryodhana.
Karna