Ekalavya, the son of the Nishadha chief, offered his right thumb to Dronacharya as Guru Dakshina and as a result, he harboured hatred towards the Yadavas and other allies of the Pandavas.
Despite Ekalavya’s disability, he was brave and was also strong enough to defeat the Pandavas.
Krishna, foreseeing a danger, had to kill Ekalavya in order to protect Dharma, as he would have joined hands with the Kauravas in the future, which could have eventually led to the defeat of the Pandavas.
To prevent this, Krishna killed Ekalavya, and praised him for his bravery and archery skills, despite his disability.
Some folklores mention that Ekalavya was given a boon to be reborn as Dhrishtadyumna, the son of Drupada, who would become the cause of Dronacharya’s death.
However, the story of Ekalavya’s rebirth has not been mentioned in the Mahabharata written by Sage Veda Vyasa, and have mostly been passed down through folk traditions.