Thread by @thekaipullai

King Drupada and Drona, were both students of Rishi Bharadwaja. Both being kids, they became close friends. As a part of their close friendship, Drupada promises to give Drona Half his kingdom once they are adults.

As students do, once their course was over, they moved on

Drupada becomes the King of Panchala, while Drona became a poor teacher and lived a poor life with his wife and son. (Guess, Teachers were paid badly those days as well).

For the sake of his family, Drona goes to Drupada as he believed his Childhood friend would take care of him

But, Drupada now being a king, insults the poor Drona and sends him away. This makes Drona take a vow to destroy him, and he goes to Hastinapur to achieve his goal.

There he is welcomed by Bheeshma and is made the teacher for both the Kauravas and the Pandavas.

Once Drona teaches everything he knows to the 105 of them, as a Gurudakshina, he asks them to defeat Drupada and bring him as a prisoner. The Kauravas fail, but Arjuna and the Pandavas capture him.

Drona then let's Drupada go but takes away, half his Kingdom. Vengeance achieved

But that only signals the beginning of a new Vengeance. This time, from Drupada. He performs some Yagna, with the explicit intention of getting a son, whose sole purpose of existence is to Kill Drona. He begets the twins, Draupadi and Drishtadyumna. He bides his time.

Fast forward to the Mahabharata, when Drupada and Drona are on the opposite sides in the war. On the 15th day, Drona kills his old Friend Drupada.

His Son Drishtadyumna then kind of illegally kills Drona, while he is meditating about the "death of his Son".

End of Vengeance 2.

Which sets into motion, Vengeance 3. This time from Ashwattama, Drona's son. On the last day of the war, Ashwathama, enters the Pandavas camp, at night, while the 5 of them and Lord Krishna are away to kill everyone and avenge his father's death

He starts of by killing Drishtadyumna, not by sword as Honour dictated, but by smothering him to death. Not only that, he kills everyone else who has survived, like Shikhandi etc. He then proceeds to kill all the sons of Draupadi. While they are sleeping.

And he launches the Brahmastra, at Uttara's womb, to wipe out Pandava lineage, completely.

This is thankfully stopped by Lord Krishna, who then curses Ashwttama to roam around in forests, with blood and pus, for eternity as death won't come to him

Two great families, were wiped out because of Vengeance. And Ego. All Drupada had to do, was to make Drona Happy.

He easily could have done it. He was a king. But he didn't. And his entire lineage paid the price.

Drona too could have let go of the hatred. But he didn't.

And he paid the price by going away with his name tarnished. Instead of Saying, what a Great Teacher, we have a but, against his name.

All for Vengeance.