Ashwathama

Ashwatthama  was the son of guru Dronacharya. He is one of the seven Chiranjeevins.

Dronacharya loved him dearly. False rumours about his death in the Kurukshetra war led to the death of his father at the hands of Prince Dhrishtadyumna. A vengeful Ashwatthama obtained permission from the dying Duryodhana to brutally murder Dhrishtadhyumna after the war had officially ended. Ashwathama at the end of the war promised Duryodhana that he would kill the Pandavas, and attacked the Pandava camp in the middle of the night, but by error ended up murdering the 5 sons of the Pandavas by Draupadi.

The Pandavas, incensed by this act, chased him resulting in his fight with Arjuna. Ashwatthama invoked the 'Brahmastra' against Arjuna and Arjuna in response invoked it too. Fearing the destruction of the world, the sages advised both to take back their weapons. While Arjuna could do so, Ashwathama  could not and was given the option of choosing any single target to destroy. Out of spite, Ashwathama directed the weapon to the womb of Uttara, Arjuna's daughter-in-law.

At this time, Uttara was carrying the unborn Parikshit, son of Abhimanyu, who upon birth would be the future heir to all the Pandava brothers. The Brahmastra weapon was successful in fatally burning the foetus, but Krishna revived the stillborn child and cursed Ashwatthama with leprosy and to roam the world for 3,000 years as an unloved castaway. In another version, it is believed that he is cursed to remain alive till the end of the Kaliyuga.