Vrishketu was the youngest son of Karna. He did not participate in the Mahabharat war because of his young age. After the war when the Pandavs found out about their real relationship with Karna, Arjuna took himvrishketu as his ward.
During Yudhishthir’s Ashwamedh yagya, Vrishaktu accompanied his uncle and teacher Arjuna.
Babhruvahan stopped the horse and killed Vrishaketu and Arjuna in battle. He regretted it when he found out that Arjuna was his father.
Later Arjuna was brought back to life by his wife Ulupi and Shrikrishna revived Vrishaketu.
When the Pandavs left for their final journey they made Vrishaketu the king of Indraprastha.